diff --git a/include/functions_category.inc.php b/include/functions_category.inc.php
index 7bf8fb0f2..d0124aac9 100644
--- a/include/functions_category.inc.php
+++ b/include/functions_category.inc.php
@@ -602,4 +602,192 @@ function remove_computed_category(&$cats, $cat)
   unset($cats[$cat['cat_id']]);
 }
 
+/**
+ * Return the list of image ids corresponding to given categories.
+ * AND & OR mode supported.
+ *
+ * @param int[] $cat_ids
+ * @param string mode
+ * @param string $extra_images_where_sql - optionally apply a sql where filter to retrieved images
+ * @param string $order_by - optionally overwrite default photo order
+ * @param bool $user_permissions
+ * @return array
+ */
+function get_image_ids_for_categories($cat_ids, $mode='AND', $extra_images_where_sql='', $order_by='', $use_permissions=true)
+{
+  global $conf;
+
+  if (empty($cat_ids))
+  {
+    return array();
+  }
+
+  $query = '
+SELECT id
+  FROM '.IMAGES_TABLE.' i
+    INNER JOIN '.IMAGE_CATEGORY_TABLE.' ic ON id=ic.image_id
+  WHERE category_id IN ('.implode(',', $cat_ids).')';
+
+  if ($use_permissions)
+  {
+    $query.= get_sql_condition_FandF(
+      array(
+        'forbidden_categories' => 'category_id',
+        'visible_categories' => 'category_id',
+        'visible_images' => 'id'
+        ),
+      "\n  AND"
+      );
+  }
+
+  $query.= (empty($extra_images_where_sql) ? '' : " \nAND (".$extra_images_where_sql.')').'
+  GROUP BY id';
+
+  if ($mode=='AND' and count($cat_ids)>1)
+  {
+    $query .= '
+  HAVING COUNT(DISTINCT category_id)='.count($cat_ids);
+  }
+  $query .= "\n".(empty($order_by) ? $conf['order_by'] : $order_by);
+
+  return query2array($query, null, 'id');
+}
+
+/**
+ * Return a list of categories corresponding to given items.
+ *
+ * @param int[] $items
+ * @param int $max
+ * @param int[] $excluded_cat_ids
+ * @return array [id, name, counter, url_name]
+ */
+function get_common_categories($items, $max=null, $excluded_cat_ids=array())
+{
+  if (empty($items))
+  {
+    return array();
+  }
+
+  $query = '
+SELECT
+    c.id,
+    c.uppercats,
+    count(*) AS counter
+  FROM '.IMAGE_CATEGORY_TABLE.'
+    INNER JOIN '.CATEGORIES_TABLE.' c ON category_id = id
+  WHERE image_id IN ('.implode(',', $items).')';
+
+  if (!empty($excluded_cat_ids))
+  {
+    $query.='
+    AND category_id NOT IN ('.implode(',', $excluded_cat_ids).')';
+  }
+
+  $query .='
+  GROUP BY c.id
+  ORDER BY ';
+  if (isset($max))
+  {
+    $query .= 'counter DESC
+  LIMIT '.$max;
+  }
+  else
+  {
+    $query .= 'NULL';
+  }
+
+  $result = pwg_query($query);
+  $cats = array();
+  while ($row = pwg_db_fetch_assoc($result))
+  {
+    $cats[ $row['id'] ] = $row;
+  }
+
+  return $cats;
+}
+
+function get_related_categories_menu($items, $excluded_cat_ids=array())
+{
+  global $page;
+
+  $common_cats = get_common_categories($items, null, $excluded_cat_ids);
+  // echo '<pre>'; print_r($common_cats); echo '</pre>';
+
+  if (count($common_cats) == 0)
+  {
+    return array();
+  }
+
+  $cat_ids = array();
+  // now we add the upper categories and useful values such as depth level and url
+  foreach ($common_cats as $cat)
+  {
+    foreach (explode(',', $cat['uppercats']) as $uppercat)
+    {
+      @$cat_ids[$uppercat]++;
+    }
+  }
+
+  $query = '
+SELECT
+    id,
+    name,
+    permalink,
+    id_uppercat,
+    uppercats,
+    global_rank
+  FROM '.CATEGORIES_TABLE.'
+  WHERE id IN ('.implode(',', array_keys($cat_ids)).')
+;';
+  $cats = query2array($query);
+  usort($cats, 'global_rank_compare');
+
+  $index_of_cat = array();
+
+  foreach ($cats as $idx => $cat)
+  {
+    $index_of_cat[ $cat['id'] ] = $idx;
+    $cats[$idx]['LEVEL'] = substr_count($cat['global_rank'], '.') + 1;
+
+    // if the category is directly linked to the items, we add an URL + counter
+    if (isset($common_cats[ $cat['id'] ]))
+    {
+      $cats[$idx]['count_images'] = $common_cats[ $cat['id'] ]['counter'];
+
+      $url_params = array();
+      if (isset($page['category']))
+      {
+        $url_params['category'] = $page['category'];
+
+        $url_params['combined_categories'] = array($cat);
+        if (isset($page['combined_categories']))
+        {
+          $url_params['combined_categories'] = array_merge($page['combined_categories'], array($cat));
+        }
+      }
+      else
+      {
+        $url_params['category'] = $cat;
+      }
+
+      $cats[$idx]['url'] = make_index_url($url_params);
+    }
+
+    // let's find how many sub-categories we have for each category. 3 options:
+    // 1. direct sub-albums
+    // 2. total indirect sub-albums
+    // 3. number of sub-albums containing photos
+    //
+    // Option 3 seems more appropriate here.
+    if (!empty($cat['id_uppercat']) and @$cats[$idx]['count_images'] > 0)
+    {
+      foreach (array_slice(explode(',', $cat['uppercats']), 0, -1) as $uppercat_id)
+      {
+        @$cats[ $index_of_cat[ $uppercat_id ] ]['count_categories']++;
+      }
+    }
+  }
+
+  return $cats;
+}
 ?>
diff --git a/include/functions_html.inc.php b/include/functions_html.inc.php
index 417b5f19f..01c54e79d 100644
--- a/include/functions_html.inc.php
+++ b/include/functions_html.inc.php
@@ -441,6 +441,55 @@ function get_tags_content_title()
   return $title;
 }
 
+/**
+ * Returns the breadcrumb to be displayed above thumbnails on combined categories page.
+ *
+ * @return string
+ */
+function get_combined_categories_content_title()
+{
+  global $page;
+
+  $title = l10n('Albums').' ';
+
+  $is_first = true;
+  $all_categories = array_merge(array($page['category']), $page['combined_categories']);
+  foreach ($all_categories as $idx => $category)
+  {
+    $title.= $is_first ? '' : ' + ';
+    $is_first = false;
+
+    $title.= get_cat_display_name(array($category));
+
+    if (count($all_categories) > 1) // should be always the case
+    {
+      $other_cats = $all_categories;
+      unset($other_cats[$idx]);
+
+      $params = array(
+        'category' => array_shift($other_cats),
+        );
+
+      if (count($other_cats) > 0)
+      {
+        $params['combined_categories'] = $other_cats;
+      }
+      $remove_url = make_index_url($params);
+
+      $title.=
+        '<a id="TagsGroupRemoveTag" href="'.$remove_url.'" style="border:none;" title="'
+        .l10n('remove this tag from the list')
+        .'"><img src="'
+          .get_root_url().get_themeconf('icon_dir').'/remove_s.png'
+        .'" alt="x" style="vertical-align:bottom;" >'
+        .'<span class="pwg-icon pwg-icon-close" ></span>'
+        .'</a>';
+    }
+  }
+
+  return $title;
+}
+
 /**
  * Sets the http status header (200,401,...)
  * @param int $code
@@ -501,6 +550,7 @@ function register_default_menubar_blocks($menu_ref_arr)
   $menu->register_block( new RegisteredBlock( 'mbTags', 'Related tags', 'piwigo'));
   $menu->register_block( new RegisteredBlock( 'mbSpecials', 'Specials', 'piwigo'));
   $menu->register_block( new RegisteredBlock( 'mbMenu', 'Menu', 'piwigo'));
+  $menu->register_block( new RegisteredBlock( 'mbRelatedCategories', 'Related albums', 'piwigo') );
 
   // We hide the quick identification menu on the identification page. It
   // would be confusing.
diff --git a/include/functions_url.inc.php b/include/functions_url.inc.php
index a0637f8c3..0a27d03d3 100644
--- a/include/functions_url.inc.php
+++ b/include/functions_url.inc.php
@@ -348,6 +348,18 @@ function make_section_in_url($params)
         {
           $section_string.= $params['category']['permalink'];
         }
+
+        if (isset($params['combined_categories']))
+        {
+          foreach ($params['combined_categories'] as $category)
+          {
+            $section_string.= '/'.$category['id'];
+            if ( $conf['category_url_style']=='id-name' )
+            {
+              $section_string.= '-'.str2url($category['name']);
+            }
+          }
+        }
       }
 
       break;
@@ -421,13 +433,23 @@ function parse_section_url( $tokens, &$next_token)
     $page['section'] = 'categories';
     $next_token++;
 
-    if (isset($tokens[$next_token]) )
+    $i = $next_token;
+
+    while (isset($tokens[$next_token]))
     {
       if (preg_match('/^(\d+)(?:-(.+))?$/', $tokens[$next_token], $matches))
       {
         if ( isset($matches[2]) )
           $page['hit_by']['cat_url_name'] = $matches[2];
-        $page['category'] = $matches[1];
+
+        if (!isset($page['category']))
+        {
+          $page['category'] = $matches[1];
+        }
+        else
+        {
+          $page['combined_categories'][] = $matches[1];
+        }
         $next_token++;
       }
       else
@@ -480,6 +502,24 @@ function parse_section_url( $tokens, &$next_token)
       }
       $page['category']=$result;
     }
+
+    if (isset($page['combined_categories']))
+    {
+      $combined_categories = array();
+
+      foreach ($page['combined_categories'] as $cat_id)
+      {
+        $result = get_cat_info($cat_id);
+        if (empty($result))
+        {
+          page_not_found(l10n('Requested album does not exist'));
+        }
+
+        $combined_categories[] = $result;
+      }
+
+      $page['combined_categories'] = $combined_categories;
+    }
   }
   elseif ( 'tags' == @$tokens[$next_token] )
   {
diff --git a/include/menubar.inc.php b/include/menubar.inc.php
index 7cb65c3e5..46fd265bc 100644
--- a/include/menubar.inc.php
+++ b/include/menubar.inc.php
@@ -101,6 +101,34 @@ function initialize_menu()
     $block->template = 'menubar_categories.tpl';
   }
 
+//------------------------------------------------------------ related categories
+  $block = $menu->get_block('mbRelatedCategories');
+
+  if ($block != null and !empty($page['items']))
+  {
+    $exclude_cat_ids = array();
+    if (isset($page['category']))
+    {
+      $exclude_cat_ids = array($page['category']['id']);
+      if (isset($page['combined_categories']))
+      {
+        foreach ($page['combined_categories'] as $cat)
+        {
+          $exclude_cat_ids[] = $cat['id'];
+        }
+      }
+    }
+
+    $block->data = array(
+      'MENU_CATEGORIES' => get_related_categories_menu($page['items'], $exclude_cat_ids),
+    );
+
+    if (!empty($block->data['MENU_CATEGORIES']) )
+    {
+      $block->template = 'menubar_related_categories.tpl';
+    }
+  }
+
 //------------------------------------------------------------------------ tags
   $block = $menu->get_block('mbTags');
   if ( $block!=null and 'picture' != script_basename() )
diff --git a/include/section_init.inc.php b/include/section_init.inc.php
index 586aec7fc..db4c30460 100644
--- a/include/section_init.inc.php
+++ b/include/section_init.inc.php
@@ -211,7 +211,11 @@ $forbidden = get_sql_condition_FandF(
 // +-----------------------------------------------------------------------+
 if ('categories' == $page['section'])
 {
-  if (isset($page['category']))
+  if (isset($page['combined_categories']))
+  {
+    $page['title'] = get_combined_categories_content_title();
+  }
+  elseif (isset($page['category']))
   {
     $page = array_merge(
       $page,
@@ -231,7 +235,17 @@ if ('categories' == $page['section'])
   }
 
   // GET IMAGES LIST
-  if
+  if (isset($page['combined_categories']))
+  {
+    $cat_ids = array($page['category']['id']);
+    foreach ($page['combined_categories'] as $category)
+    {
+      $cat_ids[] = $category['id'];
+    }
+
+    $page['items'] = get_image_ids_for_categories($cat_ids);
+  }
+  elseif
     (
       $page['startcat'] == 0 and
       (!isset($page['chronology_field'])) and // otherwise the calendar will requery all subitems
diff --git a/language/en_UK/common.lang.php b/language/en_UK/common.lang.php
index a6a4a0657..649387757 100644
--- a/language/en_UK/common.lang.php
+++ b/language/en_UK/common.lang.php
@@ -414,4 +414,5 @@ $lang['Link: %s'] = 'Link: %s';
 $lang['Your authentication key is no longer valid.'] = 'Your authentication key is no longer valid.';
 $lang['Invalid username or password!'] = 'Invalid username or password!';
 $lang['generate random password'] = 'generate random password';
+$lang['Related albums'] = 'Related albums';
 ?>
diff --git a/language/fr_FR/common.lang.php b/language/fr_FR/common.lang.php
index 082d80b2e..96e4861cf 100644
--- a/language/fr_FR/common.lang.php
+++ b/language/fr_FR/common.lang.php
@@ -412,4 +412,5 @@ $lang['Album name, Z &rarr; A'] = 'Nom de l\'album, Z &rarr; A';
 $lang['Link: %s'] = 'Lien: %s';
 $lang['Your authentication key is no longer valid.'] = 'Votre clef d\'identification n\'est plus valide.';
 $lang['Invalid username or password!'] = 'Nom d\'utilisateur ou mot de passe invalide !';
-$lang['generate random password'] = 'générer un mot de passe aléatoire';
\ No newline at end of file
+$lang['generate random password'] = 'générer un mot de passe aléatoire';
+$lang['Related albums'] = 'Albums liés';
\ No newline at end of file
diff --git a/themes/default/template/menubar_related_categories.tpl b/themes/default/template/menubar_related_categories.tpl
new file mode 100644
index 000000000..1d1e0837e
--- /dev/null
+++ b/themes/default/template/menubar_related_categories.tpl
@@ -0,0 +1,28 @@
+<dt>
+	{'Related albums'|@translate}
+</dt>
+<dd>
+{assign var='ref_level' value=0}
+{foreach from=$block->data.MENU_CATEGORIES item=cat}
+  {if $cat.LEVEL > $ref_level}
+  <ul>
+  {else}
+    </li>
+    {'</ul></li>'|@str_repeat:($ref_level-$cat.LEVEL)}
+  {/if}
+    <li>
+  {if isset($cat.url)}
+      <a href="{$cat.url}" title="{$cat.TITLE}">{$cat.name}</a>
+  {else}
+      {$cat.name}
+  {/if}
+  {if $cat.count_images > 0}
+      <span class="badge" title="{$cat.count_images|translate_dec:'%d photo':'%d photos'}">{$cat.count_images}</span>
+  {/if}
+  {if $cat.count_categories > 0}
+      <span class="badge badgeCategories" title="{'sub-albums'|translate}">{$cat.count_categories}</span>
+  {/if}
+  {assign var='ref_level' value=$cat.LEVEL}
+{/foreach}
+{'</li></ul>'|@str_repeat:$ref_level}
+</dd>
diff --git a/themes/default/theme.css b/themes/default/theme.css
index 4930d6143..8b1d94944 100644
--- a/themes/default/theme.css
+++ b/themes/default/theme.css
@@ -113,6 +113,10 @@
   padding:0 25px;
 }
 
+#menubar .badge {
+  margin-left:5px;
+}
+
 .badge::before {
   content: '[';
 }
@@ -121,6 +125,34 @@
   content: ']';
 }
 
+.badge.badgeCategories::before {
+  content:"(";
+}
+.badge.badgeCategories::after {
+  content:")";
+}
+
+/* A nicer (more modern) way to present badge, with a background color and no brackets */
+
+/*
+.badge::before, .badge::after {
+  content:none;
+}
+
+.badge {
+  display: inline-block;
+  min-width: 5px;
+  padding: 3px 7px;
+  color: #eee;
+  line-height: 1;
+  vertical-align: middle;
+  white-space: nowrap;
+  text-align: center;
+  background-color: #666;
+  border-radius: 10px;
+}
+*/
+
 /* category and tag results paragraphs on a quick search */
 .search_results {
   font-size: 16px;
@@ -796,4 +828,4 @@ LEGEND {
 
 #TagsGroupRemoveTag span{
   display:none;
-}
\ No newline at end of file
+}