If you were going to build a hotel, you'd probably use cement and steel. Maybe you'd make it out of brick and wood. Or, if you're Don Juan Quesada, you'd make a hotel entirely out of salt.
You'll find Palacio de Sal on the edge of the largest salt flat in the world. All 30 bedrooms, the walls, and even the furniture are made of salt. Not only that, you won't find much in the way of screws, nails, or cement either – they mortared the salt blocks together using salt water, and most of the rest is made of wooden panels.