The Egg was built in 1966 by Lebanese architect Joseph Philip Karam. It was one part of a modernist set of buildings, a sort of multi-user complex including an egg-spaced shell and two high towers with spaces for leisure (shopping mall, cinema) and offices. The egg-shaped cinema was designed to hold 1,000 seats and is 24 meters wide and 11 meters high. Only one tower was finished but it was destroyed during the Civil War and the Egg was the only structure left standing there. You can read more [here] on how it should have looked like once completed.
Montasser Othman visited The Egg at night and shared some awesome pictures. I shared few and you can check out the rest [here].