The flag of San Marino was officially adopted on April 6, 1862. It is one of the world's oldest flag. San Marino claims to be the oldest republic in the world which is still existent. The flag of San Marino consists of two horizontal stripes of white and blue respectively. The coat of arms of San Marino is placed in the center of the San Marino flag. The blue stripe symbolizes the sky and the white color stands for the mountains and snow which caps Mt. Titano, San Marino's highest point. The coat of arms has a shield, flanked by a wreath, a crown underneath and on top a scroll bearing the word “Libertas” (liberty). (source)
Thank you Renato!