Some facts and figures about daredevil Nik Wallenda's Friday night wire-walk over Niagara Falls:
Length of wire: 1,800 feet
Weight: 7 tons
Diameter: 2 inches
How it's installed: Helicopter flew lighter tension wire across Niagara Gorge. That acts as guide for cable to be pulled by machines across the gorge.
How it's secured: Bolts are sunk deep into bedrock, several hundred yards back from each shore.
Estimated time for walk: 30-40 minutes
Wallenda footwear: Elkskin-soled shoes custom-made by his mother.
Balance pole: 30 feet long; 40 pounds
Estimated attendance: 125,000 in Canada; 4,000 on U.S. side
Direction: From the United States to Canada
Weather forecast for Friday night: Temperatures in the low 60s with winds out of the east at 10 mph or less
Height of Horseshoe Falls (where Wallenda will cross): 170 feet
Height of cable above brink: 20 feet
Volume of water: 600,000 gallons per second.