Temple of Jupiter Heliopolitanus, Baalbek

Wikipedia provides a brief overview of the history of the temple site on the page for Baalbek city. and detail of the temple on the page "Temple of Jupiter (Roman Heliopolis)".  There was a temple to Baal here long before the Roman era, but the vast Roman structure was begun by Julius Caesar, continued by Augustus, extended by Nero and Trajan, and finally destroyed by earthquakes and pillaged in the reign of Theodosius.

 For a full bibliography and extensive discussion of the large temple see Aliquot¹. 

The Interactive Bible website provides an excellent collection of pictures connected to a rollover map. 

Taylor provides a fine collection of photographs from the 1960s².

References

1. ↑Julien Aliquot (2009). La Vie religieuse au Liban sous l'Empire romain: Békaa-Nord. Beyrouth : Presses de l’Ifpo, pp. 282-289, Section 54 A.
2. ↑George Taylor (1967). The Roman Temples of Lebanon. Beirut : Dar el Mashreq Publishers. Plates 33 - 41.