Watch: Sonic Boom Shakes French Open

A tennis match at the French Open came to a brief stop today when an enormous boom shook the city of Paris, leaving players and officials concerned about what may have occurred outside the stadium. The unsettling incident reportedly took place as Dominik Koepfer was preparing to serve to his opponent Stan Wawrinka. Suddenly, a monstrous sound pierced the near-silent setting, causing Koepfer to visibly recoil and then look around in confusion.

After a short pause, the match eventually resumed while security officers scrambled to find out what had just happened. "It was kind of weird, we both stopped. We both looked at each other and didn't know what it is," Koepfer recalled, "it was a weird feeling, for one or two points I thought about it." The unease felt by the players was shared by residents of the iconic city which has been struck by terror attacks in recent years.

Check out video of the odd moment and find out what caused the boom at the Coast to Coast AM website.