Regardless of the chilly weather, you can see 80 percent of the inhabitants of Antwerp Zoo year-round thanks to specially-designed enclosures. Highlights of the zoo include the Valley of the Great Apes, home to gorillas and chimpanzees; the Skywalk, from which you can soak up panoramic views of the historic garden; the aquarium, which a floor-to-ceiling observation window; and the Flemish Garden, home to two koala bears. For discounted rates to both attractions, opt for a combo ticket that covers both the zoo and the Aquatopia aquarium.