51-year-old Zak has spent the last eight years touring the globe and trying out his terrifying high-altitude wire-walking wherever he can find the right spot.
Zak, pictured here walking across a chasm in Yosemite National Park on a 173-metre rope, thrives on walking across chasms, over tiny inch-wide strips of material.
Leap of faith: As Zak crosses the gap between Lost Arrow on El Capitan, he says he remains 'super-focused'
Sunset view: As it gets darker, Zak is not fazed, but continues to walk
Zak, from Scharnitz in Austria, said he 'loses himself' when he is walking, becoming hyper-focused as he does so.
'If you think about anything else it could mean death,' he explained. 'What I do is not about adrenaline,' he said. 'Walking a highline is my way, it's just what I do.'
Zak is regarded by fans as a pioneer in the field.
Looking down: Zak steps out over the crowd in Munich, Germany, with a steady foot
Just visible: You can just about see Heinz Zak walking across his highline over El Capitan in Yosemite National Park
His fascination with the sport began in the 1980s, when he visited Yosemite National Park with some friends and discovered a slackline.
He has travelled through Austria, Germany, America, Italy and the Czech Republic.
Besides the highlining shown here, Zak also enjoys slacklining, where he crosses lakes just feet from the surface.
Long-term thing: Zak has been interested in high and slack lining since the 1980s but has come to prominence in recent years
Slacklining: Zak walks across a lake in Austria, ignoring the picture-perfect view to concentrate on getting across without falling in