A water main break in Cambridge has shut down part of Harvard Square Friday. Watch reportThe break was reported at about 11:30 p.m. Thursday near JFK and Mt. Auburn Streets in Cambridge, according to police. A man fell into a sinkhole created by the break, but was not injured.Crews have isolated the water main break and are set to begin repairs. Access to water has been turned back on to all affected businesses. There is no estimate as to when repairs will be completed. "It's a 12 inch water main that broke. It goes under a duct, a duct bank, and it does under and then comes back up. So what they have to do now is cut a piece out, on each side, and repair it," said Paul Carrington of the Cambridge Water Department.The break sent water gushing out, flooding the intersection and several businesses, including the Curious George Store in Harvard Square. Owner Adam Hirsch was shocked when he saw how much water was in the basement storage area."(The water) was high enough for our jaw to drop and for us to be concerned," he said.It's not yet clear how much merchandise was destroyed, but Hirsch isn't letting the water main break dampen his spirits."You know, Harvard Square, you have old water mains and this type of thing happens," he said.Inbound traffic to Harvard Square from Memorial Drive is closed, and traffic coming east from Mt. Auburn Street is being diverted to Eliot to JFK Street outbound to Memorial Drive, police said.Motorists are encouraged to avoid the area Friday, and likely through the weekend, police said.The Cambridge Water Department and Department of Public Works are working to repair the break.