The Elfstedentocht (or, in West Frisian, Alvestêdetocht, English translation: “Eleven Cities Tour”), at 200 km, is the world’s largest and longest speed skating competition and leisure skating tour, and is held in the province of Friesland, Netherlands only when the ice along the entire course is 15 cm thick.
The first organized tour was held in 1909. After this race, the Vereniging De Friesche Elf Steden (Association of the Eleven Frisian Cities)  was established to take care of the organisation.
The Elfstedentocht of 1963 is known as “The hell of ’63” when only 1% of the contestants finished the race, due to the extremely low temperatures -18°C and a harsh eastern wind.
So far it has been organized 15 times, the last one being in 1997.
The temperatures in late January and early February 2012 have heightened the expectations of a 2012 Elfstedentocht. On 2 February 2012, it was reported that 95% of various locks that controlled the water flow in the canals had been adjusted to maximise the ice thickness. On the same day, the Dutch weather meteorological service forecast that temperatures would not rise above freezing until Wednesday 8 February at the earliest and that the thickness of the ice would be 15 cm from Tuesday 7 February until Saturday 11 February.
It’s not something I’ll rush to the Netherlands for to watch, but I will be keeping a live-feed open in the corner of my desktop so I can watch a bit