Nik Wallenda, a member of the famed "Flying Wallendas" family of aerialists, successfully walked across a 2-inch-wide (5-cm) cable on Friday night over Niagara Falls Gorge.
Wallenda walked from the U.S. side of the falls to the Canadian side, a journey of 1,800 feet (550 metres) above treacherous waters and rocks. The walk is 150 feet (46 metres) above the falls, he said.
More than a century ago, an aerialist known as the Great Blondin walked a high wire strung farther down the gorge, but a trek over the brink of the falls has never been attempted.
There were 4,000 tickets sold for the event. Crowds began gathering early on Friday.
Wallenda's great-grandfather Karl Wallenda died in 1978 during a walk between two buildings in Puerto Rico at age 73. Wallenda repeated that walk last year with his mother.
Wallenda said he had obtained permits for a future walk over the Grand Canyon in Arizona, which would be the first ever attempted and roughly three times longer than the walk over Niagara Falls.