There’s slacklining in your backyard, and then there’s walking a piece of half-mile-long piece of webbing strung between two high-rise buildings across a river. Estonian slackliner Jaan Roose prefers the latter. In his latest stunt across the New Meuse river in Rotterdam, The Netherlands, he walked one of the longest and steepest urban highlines ever – the anchors had a 130-foot height difference.