Prague’s annual festival of summer circus, Letní Letná, is one of the Czech capital’s most highly anticipated events. This year the festival, nearly three weeks of pageantry and performance, kicks off on the evening of August 14th (6 pm) with a dazzling highwire act: world-renowned tightrope walker Tatiana-Mosio Bongonga will cross a 350-meter tightrope 35 meters above the Vltava River.