Great Pyramid of Giza

The Great Pyramid of Giza, is ne of the seven wonders of the world, and stands on the northern edge of the Giza Plateau, located about 10 miles west of Cairo. It is composed of over 2 ½ million blocks of limestone, which weigh from 2 to 70 tons each.
It's base covers over 13 acres and its volume is around 90,000,000 cubic feet. You could build 30 Empire State buildings with its masonry. It is 454 feet high which is equivalent to a modern 48-story building. There are currently 203 courses or steps to its summit. Each of the four triangular sides slope upward from the base at an angle of 51 degrees 51 minutes and each side has an area of 5 1/2 acres. The joints between adjacent blocks fit together with optical precision and less than a fiftieth of an inch separates the blocks. The cement that was used is extremely fine and strong and defies chemical analysis. Today, with all our modern science and engineering, we would not be able to build a Great Pyramid of Giza. The Great Pyramid is thought to have been erected around 2600 BC during the reign of Khufu (Cheops). Next to the Great Pyramid stands 2 additional large pyramids. The slightly smaller one is attributed to Cheop's son and successor , Kephren. The other, still smaller, is attributed to Kephren’s successor, the grandson of Cheops, Mykerionos. To the south-east of the Great Pyramid lies the Sphinx. The total number of identified pyramids in Egypt is about 80.
Source: http://www.gizapyramid.com/overview.htm

Khufu's pyramid at Giza showing the plan of passages and burial chamber.  

Some believe that his pyramid at Giza was built by slaves but this is not true. One hundred thousand people worked on it for three months of each year. This was the time of the Nile's annual flood which made it impossible to farm the land and most of the population was unemployed. He provided good food and clothing for his workers and was kindly remembered in folk tales for many centuries. There are three pyramids at Giza, each of which once had an adjoining mortuary temple. Attached to this temple would have been a covered causeway descending down to a valley temple, near the Nile. The 'great' pyramid itself is truly an astonishing work of engineering skill - for over four thousands years, until the modern era, it was the tallest building in the world. Source: http://www.eyelid.co.uk/pyramid3.htm