Renowned tightrope-walker Nikolas Wallenda shocked onlookers as he stumbled and seemed nearly to fall while completing a walk above Baltimore's Inner Harbor.

Wallenda, 33, is a member of the Wallenda family, a high wire-walking dynasty that dates back to Germany in the early 1900s. Using no safety net, Wallenda completed the 300-foot journey while 100 feet in the air, but gave fans a startle when he wobbled close to the end.

While confidently but carefully moving through the walk, Wallenda placed his left foot on the wire, but seemed to slip ever so slightly, and then caught himself on a shin as he almost fell but then recovered. Screams and gasps could be heard from the crowd below as he made the apparent error.

The nail-biting and utterly silent final moments of his walk end with an uproar of applause, and once he is safe, Wallenda responds to the crowd with a self-assured cheer.

"I made it … My heart jumped into my throat," Wallenda said later of the slip.

Wallenda, who did the walk in Baltimore as a stunt to mark the opening of a Ripley's Believe It or Not museum, plans to be the first person in more than a century to walk a tightrope over Niagara Fall, a feat he is set to attempt this summer.

The Flying Wallendas are a generations-old circus and daredevil stunt performing family.  Dating back to Karl Wallenda, who was born in Magdeburg, Germany after the turn of the 20th century, the family toured Europe throughout the 1900s.

Nikolas, who is Karl Wallenda's great-grandson, was following in his footsteps, as his great-granddad performed a similar high-wire walk in 1973, five years before he died from a 10-story fall at the Condado Plaza Hotel in San Juan, Puerto Rico.