Colombia has diverse physical and human geography. It has no seasons and access to both the Caribbean and Pacific oceans. The longest river is the Magdalena River, and the most colorful river is the Caristales. The population is over 48 million, making it the third most populous country in South America. Colombia has a presidential representative democratic republic form of government led by President Juan Manuel Santos. Catholicism was the dominant religion since colonial times but other faiths are now constitutionally protected. Traditional music and dance like Bambuco reflect Colombia's cultural identity.