Within the genus Homo, cranial capacity again doubled from H. habilis through Homo ergaster or H. erectus to Homo heidelbergensis by 0.6 million years ago. The cranial capacity of H. heidelbergensis overlaps with the range found in modern humans.
The original height of the Pyramid was 146.5 m (488 ft), but today it is only 137 m (455 ft) high, the 9 m (33 ft) that is missing is due to the theft of the fine quality white Tura limestone covering, or casing stones, for construction in Cairo. It is still the tallest pyramid.
Many international media, businesses, and organizations have regional headquarters in the city; the Arab League has had its headquarters in Cairo for most of its existence. With a population of 6.76 million spread over 453 square kilometers (175 sq mi), Cairo is by far the largest city in Egypt. An additional 9.5 million inhabitants live in close proximity to the city. Cairo, like many other mega-cities, suffers from high levels of pollution and traffic.