A cruise ship is a large passenger ship used mainly for vacationing. Unlike ocean liners, which are used for transport, cruise ships typically embark on round-trip voyages to various ports of call, where passengers may go on tours known as "shore excursions". Cruise ships are designed for the purpose of providing passengers with a holiday including accommodation and entertainment prioritizing onboard amenities and comfort. They are usually very large and able to accommodate hundreds to thousands of people, depending on the size of the ship. Cruise ships are organized much like floating hotels, with a complete hospitality staff in addition to the usual ships crew. They offer a wide range of amenities and activities, including round-the-clock meals, daily and nightly entertainment, various pools, fitness facilities, games, shopping, and even some adventure-type activities such as a rock wall or surfing simulator right on the cruise ship. Most cruise ships have come to resemble floating cities, and cruising is often all-inclusive.