The de Young Museum’s observation tower juts above Golden Gate Park like the mast of a copper-clad ship in a sea of eucalyptus. Stowed below is a world-class permanent collection that ranges from American painters to African sculpture with surprising ease. Highlights include Cornelia Parker’s “Anti-Mass,” Ruth Asawa’s wire abstracts, and Pop Art painter Wayne Thiebaud’s “Three Machines.” Often open late on Fridays for cocktails, live music, and artist demonstrations.