Mt saint helens a national monument and active volcano has a history dating back 40 000 years she is one of 5 washington state volcanoes it was may 18 1980 when the eruption brought this quiet mountain to the worlds attention on your tour youll see the devastation caused by the 1980 eruption and the slow return of natures flora a full day of adventure youll visit mt st helens visitor center lunch at a local restaurant and johnston ridge visitor center