Dressed as the Bag Monster, Nick Vega, 17, of Martinez, above, wears about 500 plastic bags -- the number a person uses in a year -- as he walks through the crowd at the John Muir Birthday-Earth Day Celebration on April 20, at the John Muir National Historic Site in Martinez. The event featured a visit by "John Muir," portrayed by park Ranger Frank Helling; a keynote address by former Contra Costa Times columnist Gary Bogue; cake in honor of Muir's 175th birthday; music, activities and self-guided tours of the Muir house.