site.btaToday's Observances: May 22

The world:

- National Day of Yemen: Unification Day (1990).

- International Day for Biological Diversity.

On this date in Bulgarian history:

1954: Diplomatic relations with Greece are restored. Established September 9, 1880, broken June 16, 1913, restored March 16, 1914. Broken again July 2, 1917 and restored August 8, 1920. Broken for the third time April 23, 1941 and restored May 22, 1954 at legation level. Promoted to embassy level July 12, 1964.

1965: A branch of the National Art Gallery is inaugurated in the crypt of Sofia's St Alexander Nevsky Cathedral.

2009: The Bulgarian Postal Union is set up in Sofia.

2012: A 5.8-5.9 magnitude earthquake epicentred between Pernik and Radomir shakes parts of Western Bulgaria, including the capital Sofia.