This document defines and describes various types of specialty hotels, including boutique hotels, capsule hotels, ice hotels, underwater hotels, and cave hotels. Boutique hotels are typically small, luxurious hotels with unique designs and amenities, while capsule hotels offer very small, basic rooms at low prices. Ice hotels are temporary structures built entirely of ice or snow that are reconstructed each year. Underwater hotels and cave hotels provide accommodation within unusual geological settings underground or under the sea.