Mount Hood, Oregon
Just as Vesuvius looms over Naples, the live volcano Mount Hood flanks the city of Portland. The mountain has eleven glaciers and five ski areas.
As the US Geological Survey reports, this symmetrical glacier-clad peak is a source of "valuable water, scenic and recreational resources" that boost agriculture and tourism.
Mount Hood has been active for 500,000 years, and has undergone two periods of eruption in the past 1500. The most recent significant ones took place in the 1780's, when the volcanic material made significant changes to the surrounding area.
The volcano made some threatening noises in the mid-1800s, and also underwent a minor eruption in 1907. Since then it's been ominously quiet. As shown by the historic eruptions that buried the ancient cities of Pompeii and Herculaneum, having a stratovolcano on your doorstep is a mixed blessing, and scientists monitor this one's potential for future activity, predicting that it could erupt within the next 75 years.