World's largest ice rink

What is believed to be the world's biggest ice rink has opened in Mexico City, double the size of Olympic rinks and taking up its famous Zocalo Square. What is more, the shift from Aztec to Arctic, so to speak, comes free to the public, the brainchild of the city's flamboyant mayor, Marcelo Ebrard.

Once the site of offerings to the gods, the Zocalo has now seen cars sacrificed to make way for the skaters. Mexico, its mayor hopes, can now rank among the world's "coolest" cities.

"It is an opportunity to compete with New York or Paris or any country," he says. "This rink is big and beautiful and this place is perfect."

In a city of 20 million people they had to build big. This rink has 74km (46 miles) of piping underneath to maintain the ice that is now attracting 12,000 very happy people a day to the Zocolo, which is 3,000 sq m (sq yd) in size.