If you were born before summer 1991, the answer is yes. Sorry if you already felt a bit long in the tooth, but it"s true: Until 30 years ago, Lake Pinatubo was just a rumble in Mount Pinatubo"s magma-filled belly. It was a calamitous eruption on June 15, 1991—one of the 20th century"s most powerful—that blew off Pinatubo"s original summit and formed a vast crater, which gradually filled with water as greenery reclaimed the summit.