Any band with a career as long and a catalog as large as those of U2 will shift and change over time; one creative well runs dry, then another is drilled. But few music act histories can be as easily divided as that of the Irish foursome. From white flags at Red Rocks to tour announcements at KMart, here's a timeline of the life of U2.

Four Lads from Dublin

Time Period: 1979-1983

Albums: "Boy," "October," "War"

Marked By: The innocent belief that a song could change the world.

Examples: "Sunday Bloody Sunday," "40"

The Irish in America

Time Period: 1984-1989

Albums: "The Unforgettable Fire," "The Joshua Tree," "Rattle and Hum"

Marked By: An exploration -- and in some cases, the theft of -- Americana in all forms.

Examples: "Angel of Harlem," "Desire"

Irony and Dance

Time Period: 1991-1999

Albums: "Achtung Baby," "Zooropa," "Pop"

Marked By: Deep influences of both European dance music and ironic detachment.

Examples: "Mofo," "Mysterious Ways," the entire PopMart tour

The Biggest Band in the World

Time Period: 2000-2004

Albums: "All That You Can't Leave Behind," "How to Dismantle an Atomic Bomb"

Marked By: Albums filled with stadium-sized choruses and global-sized ambitions.

Examples: "Beautiful Day," "Elevation," "Vertigo"

Turning Inward

Time Period: 2009-current

Albums: "No Line on the Horizon," "Songs of Innocence"

Marked By: Some of Bono's most personal and confessional lyrics.

Examples: "Iris (Hold Me Close)," "Cedarwood Road"