The Lighthouse at Alexandria, located on the ancient island of
Pharos (now a promontory within Alexandria, Egypt) was the
only one of the Seven Ancient Wonders that was both practical
and architecturally elegant. It was also the tallest building
on Earth and contained a mirror whose reflection could be seen
more than 50 km (35 miles) off-shore.
Although Ptolemy Soter conceived and began the lighthouse around
290 BC, it was completed after his death, during the reign of
his son Ptolemy Philadelphus. The architect was Sostratus, a
contemporary of Euclid, but the Alexandria Library/Mouseion
provided the detailed calculations for the lighthouse structure
and its accessories .
The lighthouse was damaged by earthquakes in 1303 and 1323.
Famous Arab traveler Ibn Battuta could not enter the lighthouse
or even climb to its doorway in 1349. The Egyptian Mamelouk
Sultan, Qaitbay, built a medieval fort on the site of the lighthouse
in AD 1480, using the fallen stone and marble.An Arab traveler
named Abou-Haggag Al-Andaloussi described the lighthouse in
detail in 1166. According to his records, it was composed of
three stages: The lowest square, 55.9 m (183.4 ft) high with
a cylindrical core; the middle octagonal with a side length
of 18.30 m (60.0 ft) and a height of 27.45 m (90.1 ft); and
the third circular 7.30 m (24.0 ft) high. Including the foundation,
the building was about 117 m (384 ft), equivalent to a 40-story
modern building. The internal core was used as a shaft to lift
the fuel needed for the fire. At the top stage, the mirror reflected
sunlight during the day while fire was used at night. A statue
of Poseidon adorned the building's summit in ancient times.
