“Human Spider” Alain Robert was arrested in London’s financial district after he scaled Heron Tower on Thursday afternoon. The illegal climb took Robert around 50 minutes, after which he was arrested for “causing a public nuisance.” “Our officers, the London Fire Brigade and the London Ambulance Service all attended this incident taking them away from genuine emergencies,” said London police commander Karen Baxter. Robert considered a few different skyscrapers for two days before deciding on the 755-foot building. “For me, it seems doable, meaning acceptable in terms of difficulties,” Robert told British news before he started climbing. “I just want to make sure I am not putting my life at risk.” London police closed down several blocks upon arriving at the scene. The endeavor was a small feat compared to Robert’s previous stunts, including climbing the world’s tallest tower—Dubai’s Burj Khalifa—in 2011. The French free climber did, however, use ropes and a harness for that challenge. Heron Tower, also known as Sales Force Tower, is London’s third-tallest building.