Get within a mile or so of San Francisco's de Young Museum, and you should require no further directions than 'keep an eye peeled for the building that looks like it was ejected from a passing UFO.' Even more than the California Academy of Sciences, its newer neighbor in Golden Gate Park, the de Young looks like an alien artifact. This machine-in-a-garden comes clad in weathered copper -- some panels shading toward brick red, others dark green -- with expanses of tiny dimples, goose bumps and holes. At one end, a shelf projects over an adjacent park; at another, a 144-foot tower angles its way upward. The de Young's tower constitutes the cheapest, quickest benefit from a visit here: a cost- and crowd-free alternative to the Coit Tower. Nine floors up, its glassed-in room provides views of, in clockwise order from the north: the Golden Gate Bridge and the Marin Headlands beyond; San Francisco's houses, hills and skyscrapers; the Academy of Sciences' porthole-pocked green roof and the 977-foot-tall Sutro Tower TV-transmitter structure; and the bulk of the de Young and Golden Gate Park. The slight sway you might feel as the tower absorbs the wind adds to the interest here. The museum itself hosts a catchall assortment of collections. If you look for a consistent thread of artistic exploration through its galleries, you might get lost. Correction: You (begin ital) will (end ital) get lost. Many of the de Young's walls meet at odd angles, and the entire building is pierced by two skinny courtyards that reach toward its center. Some rooms start small and then open up away from you; others lead down long stretches of hallway. You're best off taking a cafeteria approach: Pick a room, see what you like, then move on to whatever adjacent space looks inviting. You could begin in the museum's lower level, which holds temporary, extra-cost exhibits. On a visit in mid-May, a multimedia show on Andy Warhol's life and work filled the space; the current exhibit, 'Tutankhamun and the Golden Age of the Pharaohs,' runs through March 28. Or you could start at the top, on the de Young's second floor. One end features the museum's collections of pottery, sculpture, carvings, masks and such from Africa, New Guinea and New Zealand. On the rest of the floor, the 'Art in America' exhibition offers a series of intriguing mixes of genres and eras. Period furniture and silverware, including a particularly ornate sword and scabbard by Tiffany and Co., sit between 19th-century oils. Next to a set of Hudson River School paintings, a 2001 oil of a foggy San Quentin prison owes a debt to those earlier works. The de Young's ground floor features both its oldest and newest works: a collection of Mayan pottery, sculpture, murals and stonework; a smaller set of Native American baskets, scrimshaw, bowls and vases; and a few galleries of late-20th-century and newer art. The last section features some of the museum's more thought-provoking works. For example, Cornelia Parker's 'Anti-Mass' could be mistaken for a purely abstract mobile; its caption, however, explains that its hanging bits of blackened wood came from the ruins of a Baptist church torched in an act of racist arson. In a nearby hallway, an LED readout shows how many of the day's sunlit hours have gone by. That should be your cue to step outside, but not to leave. Next to the de Young's cafeteria, a set of sculptures rests on a lawn, and a narrow path takes you around and then into a low mound. That turns out to be a sparse, soothing 'skyspace' called 'Three Gems,' by James Turrell, a largely enclosed pit that looks straight up to the sky and yields no hint of your location. Even though you're only a few dozen feet from the building, a fresh set of directions might be in order. 