LONDON (AP) — London’s famous Tower Bridge, which crosses the River Thames in the heart of the British capital, was stuck open on Saturday, leaving traffic in chaos and onlookers amazed at the sight.

The historic bascule-and-suspension bridge failed to close after opening to allow ships to pass underneath on the Thames. City of London police tweeted shortly after 5 p.m. that the bridge was closed to pedestrians and traffic and mechanics were working to fix the problem. An hour later, police tweeted that the bridge had reopened.