The Aperture Science Enrichment Center is the setting of Portal and Portal 2, It is the location at which the company tested their experimental portal-creation technology, the Aperture Science Handheld Portal Device and also possibly the facility where the portal device was created. It is also overseen by GLaDOS, a rougue A.I. program and the lone NPC encountered in the original game.
In Portal, the player, as the protagonist Chell , learns more about the facility's history through the discovery of hidden rooms and GLaDOS's dialogue. At some point prior to the game's start, GLaDOS had usurped control of the facility and used a gaseous neuro-toxin to murder the research facility's staff.
Aperture Science was founded by Cave Johnson in 1947. Before 1947 Aperture Science was known as Aperture Fixtures and their initial purpose was to manufacture shower curtains for the American military. In later years, a series of bizarre experiments conducted by the company led to an investigation of Aperture by the U.S. Senate. Upon investigation, the Senate realized the potential of one of Aperture's experiments in portal technology and allowed the research to continue. Aperture's subsequent projects also included the creation of the Genetic Lifeform and Disk Operating System (GLaDOS).
Apperture Science was known to carry out bizarre experiments that left a majority of the test subjects dead. It's been noted that out of 10,000 test subjects Chell has been the only one to ever successfully escape.
Aperture Science's primary corporate rival is Black Mesa, the research facility that employed Half-Life
protagonist Gordon Freeman