tower as it rose. Crane 1 was erected in September 2009 and Crane 2 was erected at the beginning of October. By 20 October 2009, steel beams began appearing on site, with concrete being poured at the northern part of the site, ready for Crane 3. By March 2010, the concrete core was rising steadily at about a day. After a pause in March–April 2010, it continued rising, reaching the 33rd floor in mid-June, almost level with the top of Guy's Hospital, which stands at . On 27 July 2010, the core stopped rising, having reached the 38th floor, and was reconfigured for further construction. By mid-November 2010, the core had reached the 68th floor, with the tower's steel reaching the 40th floor and glass cladding enveloping a third of the building. In late November, the core's height exceeded , ending One Canada Square's 18-year reign as Britain's tallest building. The Shard's concrete core topped out at the 72nd floor in early 2011, standing at . The early part of January 2011 saw the installation of hydraulic screens, which were used to form the concrete floors of the hotel and apartment section of the tower, and rose with the floors up to the 69th floor. On 25 January 2011, the concrete pumps began pouring the first concrete floor at the 41st floor. By the end of February 2011, concrete flooring had risen to the 46th floor, with a new floor being poured on average every week. The cladding of the structure also progressed, mainly on the tower's "backpack". During this phase of construction, a fox was discovered living at the top of the unfinished skyscraper. The fox, named Romeo by staff, is thought to have entered the building through the central stairwell. It survived by eating scraps of food left by builders working on the incomplete structure. The fox was captured and taken to Riverside Animal Centre in Wallington. August 2011 saw steady progress in construction, with cladding enveloping more than half the building's exterior. Pouring of the concrete floors reached the 67th floor, and progression on the tower's cladding reached the 58th floor. By mid-August, the core box had been removed. By 19 September 2011, the tower's steel was approaching the height of the completed core, reaching almost . On 24 September, a final crane – at the time, the tallest ever built in Britain – was erected to