If for example there is no category for the area that you want to review, hoa do you add it ?

Trivago is structured somewhat differently to CIAO or dooyoo and does not deal in "categories". When you wish to add anything to the trivago site there are two contexts that need to be considered: "where it is" and "what it is".

As this is a site based on travel, it world is divided up into continents which are then progressively subdivided into smaller units. Countries are then sudivided into regions. So, North East England's full context is: Europe>United Kingdom>England>North East England.

Regions have "destinations" (where it is) associated with them. Destinations are cities, towns and villages and those known to the database are listed in the "All Destinations" option on the Regional front page.

If a destination is not present this is a "Missing City". See "Adding Destination" thread. It is important not to get these mixed up with "items".

"Items" (what it is) are hotels and attractions (museums, theme parks, restaurants etc) and these are associated with destinations. You can list these from the destination's front page. If the item you want does not appear, you can add it (See "Adding Item" thread)

You can add your own reviews, photographs etc to items but not destinations.

Note: you can see all the destinations, hotels and attractions on the Regional front page in the cumulative listings but you cannot add them here.