The lion habitat inside the MGM Grand casino is kind of an under-regarded attraction on the Strip. You want to go at feeding time (late afternoon, I believe) when you see the trainers interacting with the lions--otherwise the cats mostly lie about (lions are mostly nocturnal--but they aren't in the visible habitat at night). The habitat is set up so you can see it from all sides (even walk underneath), and moving around to see different vantage points is definitely recommended. Yes, you will probably wish that it was bigger, and that it was part of a larger animal sanctuary (like Sigfried & Roy's dolphin and tiger Secret Garden), but hey... it's free. As in FREE.