Elfstedentocht

The Elfstedentocht (West Frisian: Âlvestêdetocht, English: Eleven cities tour), at almost 200 kilometres (120 mi), is a speed skating match (with 200 contestants) and a leisure skating tour (with 16,000 skaters). It is held in the province of Friesland in the north of the Netherlands, touching each and every city (by history) of the province. It is held, in practice in January or February and not more than once in a year, when the natural ice along the entire course is at least 15 centimetres (6 in) thick; sometimes on consecutive years, other times with gaps that may exceed 20 years. When the ice is suitable the tour is announced, and starts within 48 hours.

Read more about Elfstedentocht:  Course and Rules, Planning and Publicity, History, Winners, The Eleven Cities, Fietselfstedentocht (Eleven Cities By Bicycle)