Because authorities did not normally give him permission for such dangerous exploits, Robert would appear at dawn on the site of whichever giant skyscraper he had chosen to climb. His exploits attract crowds of onlookers who stop to watch him climb.

As a consequence, Robert has been arrested many times, in various countries, by law enforcement officials waiting for him at the end of his climb.

In recent years, however, Robert has done his climbs with permission and sponsorship.

His rock-climbing physical training and technique allow him to climb using the small protrusions of building walls and windows (such as window ledges and frames).

Many of his climbs provide him no opportunity to rest and can last several hours. He sometimes has a small bag of climbing chalk powder fastened around his waist.

Sources: Reuters on Twitter, Wikipedia, YouTube