The "Elfstedentocht" is a speed skating race through eleven cities in Friesland, Netherlands. The race doesn't take place every year due to the fact that the canals on which the skaters race do not always freeze every winter.
How It's Used
“When there is ice, that is. This northern Dutch city, population 90,000, of straight brick homes and meandering canals, is home to the 125-mile Eleven Cities Tour, or Elfstedentocht, which takes place only when nature says so.”
—John Tagliabue, “Dutch skaters waiting, yet again, for good ice: A race not run since 1997 is in doubt,” The International Herald Tribune, February 26, 2007, p. 3.