Nik Wallenda and Niagara Falls

Nik Wallenda, 33, on Friday will try to cross Horseshoe Falls, the biggest and most spectacular of Niagara Falls’ three cascades.   (Carolyn Cole / Los Angeles Times)

Wallenda gets in a workout.   (Carolyn Cole / Los Angeles Times)

Jean Kiene of Lockport, N.Y., watches Wallenda practice near Niagara Falls.  (Carolyn Cole / Los Angeles Times)

ABC, which will televise Wallenda’s attempt Friday, demanded that he wear a safety device to prevent him from plummeting to his death during prime time.   (Carolyn Cole / Los Angeles Times)

A crowd watches Wallenda practice. The event has been more than a year in the making and required approval from park officials on both sides of Niagara Falls.  (Carolyn Cole / Los Angeles Times)

Wallenda at work. “It’s happening. This is going to be the biggest event on the planet!” said Jim Diodati, mayor of Niagara Falls, Canada.   (Carolyn Cole / Los Angeles Times)

Lights are set up along the top of the falls on the U.S. side, close to where Wallenda will begin his walk.   (Carolyn Cole / Los Angeles Times)

Tourists view Niagara Falls from the U.S. side, from which Nik Wallenda will start his walk across the wire on the left.  (Carolyn Cole / Los Angeles Times)

Nik Wallenda poses for a photo with a tourist on the day before his historic tightrope walk, which officials hope will boost tourism.  (Carolyn Cole / Los Angeles Times)

Nik Wallenda, right, takes a break near the falls on the day before his historic walk.  (Carolyn Cole / Los Angeles Times)

Nik Wallenda below the wire he plans walk to cross Niagara Falls. A rescue cage will follow him across.  (Carolyn Cole / Los Angeles Times)

A wire crosses Horseshoe Falls, where Nik Wallenda plans his historic walk.  (Carolyn Cole / Los Angeles Times)

The spray at Horseshoe Falls creates a small rainbow below the tourists taking in the view.  (Carolyn Cole / Los Angeles Times)

Nik Wallenda, shown at a news conference, says this walk will be a dream come true for him.  (Carolyn Cole / Los Angeles Times)

A view of the Canadian side of the falls, seen from Niagara, N.Y.  (Carolyn Cole / Los Angeles Times)