A cork is globally known as a wine bottle closure. Cork comes from the cork tree (Quercus Suber) which is species of oak growing in Spain or Portugal.
A Benedictine monk called Dom Perignon used conical pieces of cork to seal his bottles of sparkling wine in the 1600s.
Cork was known back in Greece and Rome to have great sealing property. Today a number of wineries are turning to synthetic corks that have the sealing properties of real cork, but do not harbor molds.