One of the most significant contributions of Trinidad and Tobago to the world of music was the invention of the steelpan. This instrument is the only acoustic instrument that was invented in the 20th century. The pan evolved from music which the island slaves created for the carnival festivities. The first steel-pans were made from oil drums. The players would beat on the end of the oil drum with bamboo to produce music and found that the areas of the drum that were hit the most frequently developed a higher pitch. From this discovery the players learned that they could change the pitch of the drum to create different notes.