This speculation also involves theories concerning whether Mallory and Irvine could have managed to climb the Second Step. Òscar Cadiach was the first to climb it in 1985 free and rated it V+. Conrad Anker led an experiment to free climb this section without using the Chinese ladder for assistance, since that equipment was not installed in 1924. In 1999, he did not manage a complete free climb as he put one foot briefly on the ladder when it blocked the only available foothold. At that time he rated the difficulty of the Second Step as 5.10—well outside of Mallory's capability. In June 2007, Anker returned as a member of the Altitude Everest Expedition 2007, and with Leo Houlding successfully free-climbed the Second Step, after removing the Chinese ladder (which was later replaced). Houlding rated the climb at 5.9, just within Mallory's estimated capabilities. Theo Fritsche climbed the step free solo on-sight in 2001 and rated it V+.