Site: Freemasons Grand Lodge (2 memorials)
WC2, Great Queen Street, Freemasons' Hall
This monolithic art deco building is the HQ of the United Grand Lodge of England and is also the main meeting place for London's Lodges. The Freemasons' website says that it was built (1927-33 by H. V. Ashley and Winton Newman) as a memorial to the Freemasons who died on active service in WW1 and was initially called the Masonic Peace Memorial but, on the outbreak of WW2 that no longer seemed appropriate so it was renamed Freemasons' Hall. Inside there is a very ornate memorial shrine commemorating the 3,225 brethren who died on active service in WW1.
This is the third Freemasons' Hall on this site: the foundation stone for the first was laid 1 May 1775 (opened 23 May 1776), the second 27 April 1864 (opened 14 April 1869), the third 14 July 1927 (opened 19 July 1933 by the Duke of Connaught, Grand Master).