The Athens Metro (Greek: Μετρό Αθήνας, Metró Athínas) is a rapid-transit system in Greece which serves the Athens conurbation and parts of East Attica. It incorporates the former Athens-Piraeus Electric Railways (ISAP), which opened as a conventional steam railway in 1869, and which was electrified in 1904 and is now part of Line 1. Beginning in 1991, Attiko Metro constructed and extended Lines 2 and 3 and the Attiko Metro Operations Company (AMEL) operated these lines from 2000 to 2011. The metro network merged in 2011 when the Greek government created the Urban Rail Transport Company (STASY), a subsidiary of the Athens Urban Transport Organisation (OASA). First Chairman and CEO of the merged company became Kostas Vassiliadis, a former Chief Engineer and later CEO of Athens-Piraeus Electric Railways. The system is noted for being modern and efficient, in its own right and in comparison to other subway systems elsewhere. It has drastically changed Athens by providing a much-needed solution to the city's traffic and air pollution problem, as well as revitalising many of the areas it serves. An extension of Line 3 is under construction towards Piraeus and also other extensions of existing lines, as well as a new line, are under consideration. The Athens Metro is actively connected with the other means of public transport, such as buses, trolleys, the Athens Tram and the Proastiakos suburban railway. Photography and video-taking is permitted across the whole Athens Metro network, however very often the security personnel might create problems for photographers.