The International Tourist Regatta on the Danube, known by the acronym TID, has been held annually since 1956 and is believed to be the world's longest rowing trip of its kind. Participants travel more than 2500 km by water for about two and a half months with luggage in a boat. The regatta starts in Germany, passes through Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria, and it ends at the Danube delta in Romania.