There were scenes of panic in Shenzhen, southern China Tuesday afternoon as one of the city's tallest skyscrapers started shaking. Thousands of workers and shoppers ran to safety as the 71-story SEG Plaza wobbled, the BBC reports. Authorities say the 21-year-old building was safely evacuated, along with some neighboring buildings, but they're not sure what caused the shaking. There were no earthquakes recorded and experts say the winds weren't strong enough to have caused tall buildings to wobble.
"One of my friends was in the building and noticed that the water bottles on the desk started to shake," says a vendor at an electronics market next to the skyscraper, per the South China Morning Post. Witnesses said the building appeared to tilt on its foundations. "The cause of the shaking is being verified by various departments," emergency management officials said in a statement. The building is currently sealed off and it's not clear when it will reopen. (Read more China stories.)