One Canada Square of London."" One Canada Square was originally designed to be high at 55 storeys, but that penetrated the permitted projection height of the flight obstruction area of the airport approach district to London City Airport, but this was extended to a height of above kerb level in consideration of the fact that One Canada Square was on the external zone of the airport approach. To comply with air traffic safety regulations, the architects took five floors off the tower. The final height of was permitted, otherwise, the developers would have had to dismantle what was necessary to fit the height
Citigroup Centre, London Citigroup Centre, London The Citigroup Centre is a building complex in London. It houses Citigroup's EMEA headquarters and is located in Canary Wharf in the city's Docklands. The centre provides of floor space across two merged buildings - 33 Canada Square (known as "CGC1") and 25 Canada Square (known as "CGC2"), and houses the bulk of Citi's UK employee base. Together, both buildings form the Citigroup Centre complex. 25 Canada Square, or Citigroup Centre 2, stands at and, alongside HSBC Tower (with which it was built in tandem), is the joint 4th-tallest building in the United Kingdom (behind The Shard,