The National Centre for the Performing Arts (NCPA), colloquially described as The Giant Egg, is an arts center containing an opera house in Beijing, the People’s Republic of China. Designed by French architect Paul Andreu, the NCPA opened in 2007 and is the largest theatre complex in Asia.

The NCPA is semi-spherical in appearance, with a long axis length of 212.20 meters in the east-west direction, a short axis length of 143.64 meters in the north-south direction, a height of 46.285 meters, an area of 119,900 square meters, and a total construction area of approximately 165,000 square meters, including 105,000 square meters of main buildings and 60,000 square meters of underground, auxiliary facilities. There are Opera hall, Music hall, theater and art exhibition halls, restaurants, audio shops, and other supporting facilities.

The exterior of the NCPA is a steel structural shell. It has a semi-ellipsoidal shape. The length of the long axis in the east-west direction of the plane projection is 212.20 m, the length of the short axis in the north-south direction is 143.64 m, and the height of the building is 46.285 m, which is slightly lower than the Great Hall of the People by 3.32 meters. The deepest part of the foundation reaches 32.5 m. It is as tall as ten floors. The large theatre shell is made up of more than 18,000 pieces of titanium metal plates, covering an area of more than 30,000 m2. Of the more than 18,000 pieces of titanium metal plates, only four are the same shape. The titanium metal plate is especially oxidized, and its surface metallic luster is very textured and has a consistent color for 15 years. The middle part is an involute glass curtain wall, which is made up of more than 1,200 pieces of ultra-white glass. The ellipsoidal shell surrounds the artificial lake, with a surface area of 34,300 square meters, with all channels, and entrances located below the water surface. Pedestrians need to enter the performance hall from an 80-meter underwater passage.

According to the requirements of Beijing’s overall planning, the height of the NCPA cannot exceed the height of the Great Hall of the People(46 meters), but the functional requirements of the NCPA cannot be loaded in the 46-meter space, so it can only develop underground. The NCPA extends ten stories underground, making 60% of the building area underground. It is the most in-depth underground project of public buildings in Beijing. The deepest place is 32.5 meters, which is directly below the stage of the Opera hall. The 17 meters underground of the NCPA is the ancient river channel of the Yongding River in Beijing. The underground of the NCPA contains abundant groundwater. The buoyancy generated by this groundwater can support a giant aircraft carrier weighing 1 million tons. Such tremendous buoyancy is enough to hold up the entire theater.

According to Wikipedia