Happy Anniversary!

Def Leppard released their fourth album, Hysteria, 25 years ago today, August 3rd, 1987.

Def Leppard released their fourth album, Hysteria, 25 years ago today, August 3rd, 1987. It remains their most successful album with more than 20-million sold worldwide. It went to number-one in the U.S. and their native England, and spawned six hit singles -- the title track, "Animal," "Pour Some Sugar on Me," "Love Bites," "Armageddon It" and "Rocket." Drummer Rick Allen came up with the album title, as it was a word he related to his 1984 auto accident, in which he lost his left arm. In 2004, Hysteria was named the 472nd best album on Rolling Stone's list of the 500 Greatest Albums of All Time.

Def Leppard are on a break from their Rock of Ages tour with Poison, but they crank things back up on Thursday in Florida.