With volcanic soil and a subtropical climate, the island of Jeju-do has become a center for tea cultivation. On a quick visit to this island off the southwestern tip of Korea, you are practically obligated (by hotel concierges, taxi drivers, travel agents) to visit the O'sulloc Tea museum. Don't let the vaguely Irish-sounding name fool you--this is one-hundred-percent Korean. Touristy, maybe. But beautiful and delicious, definitely.