Admiralty Arch was designed in 1910 by Sir Aston Webb (who also worked on Buckingham Palace).

It was designed to provide a ceremonial style entrance to the Mall, at the bottom of which lies Buckingham Palace.

A large Latin inscription along the top reads "ANNO DECIMO EDWARDI SEPTIMI REGIS VICTORI� REGIN� CIVES GRATISSIMI MDCCCCX" which translates to "In the tenth year of King Edward VII, to Queen Victoria, from most grateful citizens, 1910 - It was commissioned by King Edward VII in memory of his mother Queen Victoria.

Enjoy!
Cheers,
Phil, UK