Top 10 build­ings facts

In summer. The tower stands 320 meters (1,050 ft) tall, about the same height as an 81-storey building. Because of thermal expansion, the height varies by 15 cm (5.9 in) due to temperature.

None. Only the Great Pyramid of Giza still exists. The other Wonders of the Ancient World were destroyed: two by fire, three by earthquakes. Existence of one of them is still debated.

Empire State Building has held the title for 42 years since 1931. It was surpassed by the North Tower of the World Trade Center in 1972. An early-1970s proposal to dismantle the spire and replace it with an additional 11 floors, which would have made it once again the world's tallest at the time, was considered but ultimately rejected.

It was built quickly and under budget. The Empire State Building took only one year and 45 days to build, or 7 million man-hours. To this day, this is a record for a skyscraper of its height. Due to reduced costs during the Depression, the final costs totalled only $24.7 million instead of the estimated $43 million.

7. As no traditional organization or formal body awards or recognizes any rating over five-star deluxe, such claims are meaningless and predominantly used for advertising purposes. The Burj Al Arab hotel says the label originates from journalists and that they neither encourage its use, nor do they use it in their advertising.

Pumice. The porous light stone was used in the concrete of the dome to reduce its weight. Scientists estimated that, if normal weight concrete had been used throughout, the stresses in the arch would have been some 80% greater. The same technique was for the ceilings of the Colosseum.

Gotthard-Basistunnel (Switzerland-Italy). Tunnel da basa dal Son Gottard) is a railway tunnel through the Alps in Switzerland. With a route length of 57.09 km (35.5 mi),it is the world's longest and deepest traffic tunnel and the first flat, low-level route through the Alps.

In North Korea. The Arch of Reunification is a sculptural arch located south of Pyongyang, the capital of North Korea. It was opened in August 2001 to commemorate Korean reunification proposals put forward by Kim Il-sung.

Runit Island, Enewetok Atoll. In 1977, the United States military began decontamination of Enewetak and other islands. During the three-year, $100 million cleanup process, the military mixed more than 111,000 cubic yards (85,000 m3) of contaminated soil with Portland cement and buried it in an atomic blast crater. Today, a concrete dome covers the material.

Of Hong Kong to Macau. The Hong Kong–Zhuhai–Macau Bridge (HZMB) is a 55-kilometre (34 mi) bridge–tunnel system consisting of a series of three cable-stayed bridges, an undersea tunnel, and four artificial islands. It is both the longest sea crossing and the longest fixed link on earth. The HZMB was designed to last for 120 years and built with a cost of US$ 18.77 billion.