Arizona-Sonora Desert Museum

Walking trails wind through 21 acres of recreated Sonoran Desert habitat, with mountain lions, bighorn sheep and coyotes living in naturalistic enclosures instead of cages. The daily Raptor Free Flight program lets hawks, owls and caracaras soar untethered low over visitors' heads as they move between perches, with no leashes or restraints of any kind. A small aviary holds live hummingbirds at close range, some visitors watching birds sit on their own nests. William H. Carr and Arthur Pack founded the museum in 1952 on the then-radical idea that a zoo, a botanical garden and a natural history museum belonged together as one place, explaining a single desert ecosystem rather than keeping three separate collections. That living-museum model, animals shown in habitat rather than behind bars, has since been copied by institutions elsewhere.