The Hanging Garden of Babylon is one of the seven wonders of the world. It was built by Nebuchadnezzar II of the Kingdom of Babylon in the 6th century BC in the city of Babylon for her homesick princess, Amyitis. The aerial garden adopts the three-dimensional gardening method. The garden is placed on a four-floor platform, which is built of asphalt and bricks. The platform is supported by a 25-meter-high column, and has an irrigation system. The slave keeps pushing the handle connected with the gear to convey water to the garden. Various flowers and trees are planted in the garden, which looks like a garden hanging in the air from a distance.