Estonia celebrates the anniversary of Restoration of Independence on August 20th. It was on August 20, 1991, when Estonia declared formal independence during the Soviet military coup attempt in Moscow, reconstituting the pre-1940 state.
On 20 August 1991 the Estonian Supreme Soviet, in agreement with the Estonian Committee (the executive organ of the Estonian Congress) proclaimed Estonian independence, thus restoring the Republic of Estonia, which had been legally established in 1918 and illegally occupied in 1940 by the Soviet Union. This decision was quickly followed by the restoration of diplomatic relations and recognition of the Republic of Estonia by many countries.
Photo and source; Estonian World