1851 inside view of the Crystal Palace. Paxton, who was already a well-known gardener at the time, experimented extensively with glasshouse construction. Paxton invented the "ridge-and-furrow" roof design by combining prefabricated cast iron, laminated wood, and standard-sized glass sheets. The ridge and furrow system allows water to run off the roof while keeping the greenhouse warm in cold climates and preventing heat loss in hot climates. Joseph Paxton built eight other glasshouses for various clients between 1816 and 1851, but this one is considered his masterpiece. It has been estimated that this greenhouse cost £10,000 ($150,000 today) at the time it was built. The client was Prince Albert, who had married Queen Victoria a few years earlier. The palace was designed as a winter garden and contained trees, shrubs, flowers, and herbs from all over the world. It is said that Paxton used as much glass in its walls as possible because he wanted the palace to be as transparent as possible so people could see what lived within it even during daylight hours. Inside the palace there were three floors with an indoor garden on each floor. On the first floor there were bamboo houses where plants came from around the world were grown for the royal household. These included a Chinese house, a Japanese house, and a South American house. On the second floor there were cages where animals from around the world were kept.