The Russian flag was adopted in 21 August, 1991. It became an independent state and member of the United Nations on 26 December, 1991, only three months after.

When you trace the history of the Russian flag you find its origins in Peter the Great's visit to The Netherlands in 1699. He wanted to learn about shipbuilding and felt the need for Russia to have a naval flag too, so when he designed the flag of Russia, it was quite similar to the flag of The Netherlands but he used Russian colours. 

The design of the Russian flag is mainly based on The Netherlands flag. A lot of Slavic nations of Europe base their flag on the Russian flag, and the colours are also referred as Pan-Slavic colours. These colours represent Slavic independence and unity.