Mount Saint Helens is a few hours from Seattle, by car. The area is famous for a devastating volcanic eruption that occurred there in 1980. Its marks are quite visible: whole areas have completely lost their vegetation, other contain trees that died due to toxic fumes, and animals are scarce.
The best way to go to Mount Saint Helens is to drive by car from Seattle.
Travel tips: Check local museums to understand what happened in the area.
Please check the photos of my visit at Mount Saint Helens in September 2005.