http://agathe.gr/guide/history_of_the_excavations.html
History of the Excavations Some of the Agora monuments have never been fully buried and were explored by the Archaeological Society starting in the 19th century: the Stoa of Attalos (1859–1862, 1874, and ... The trench for the extension of the Athens–Piraeus railway in 1890–1891 also exposed remains of buildings and sculptures. ... Kress Foundation (Church of the Holy Apostles, publications), the Ford Foundation and the Rockefeller Brothers Fund (excavations, 1969–l974), and the David and Lucile Packard Foundation (excavations, 1979–1998).