Skjaldbreiður Travel Guide
Skjaldbreidur is a shield volcano in Southwest Iceland. It is indeed shaped like a broad shield, whence it derives its name.
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The volcano culminates at 1060 meters and its crater is about 300 meters in diameter. The basin of Thingvallavatn was formed in the same eruption that formed Skjaldbreidur, around 9000 years ago.