Just a few decades ago, a holiday on a hot beach was the highlight of the year for many people, but now underwater travel has caught on. So much beauty can be observed during these underwater adventures: the Great Barrier Reef, the Mariana Trench, countless schools of exotic fish, whales and deep-sea squids, the migration of lobsters to name but a handful. The itinerary and duration of a journey can be selected by the individual. What was once available only to a lucky few experts can now can be seen by everyone. Finally, holidays have become truly unforgettable thanks to underwater hotel liners.