The flag of which country, consisting of three horizontal stripes of red, white and blue (almost identical to that of the Netherlands), was first used in 1845 and officially adopted on June 23, 1972?
The flag of Luxembourg consists of three horizontal stripes, red, white and blue, and can be in 1:2 or 3:5 ratio. It was first used between 1845 and 1848 and officially adopted on June 23, 1972.