Grosvenor House Hotel sits on Park Lane in London’s Mayfair, originally built on the site of Grosvenor House, the 18th-century London residence of the Grosvenor family, who later became Dukes of Westminster. The land started as meadow until the 1730s, passed through owners like the Duke of Cumberland, and served government functions during World War I before being sold in 1925.
Commercial speculator Arthur Octavius Edwards bought the site in 1925, demolishing the mansion in 1927 to create luxury apartments, but shifted plans mid-build due to the Great Depression, turning the northern block into a hotel. Designed by Wimperis, Simpson and Guthrie with elevations by Sir Edwin Lutyens, it opened on May 14, 1929, with 472 rooms, though critics mocked its height as an “insult to taste”.
 
Interesting facts...
During the war it was protected by 10,000 sandbags and miles of blackout cloth, it sheltered U.S. Generals Eisenhower and Patton as an officers’ mess from 1943.