Dubai is known for its ultra-modern buildings, skyscrapers, the Burj Khalifa, the tallest building in the world, the Dubai Mall, the largest mall in the world, and its entertainment, restaurants, and attractions. Beaches, indoor ski slopes, amusement parks, the indoor air-conditioned Dubai Dolphinarium, and observation decks on the Burj Khalifa are attractions for family visitors. Opulent hotels and resorts include the Burj Al Arab Jumeirah, built on an artificial island with a helipad, private beach, restaurants, and spa.