If you travel to Luxor (ancient Thebes) then it will be hard to miss the spectacular
Luxor Temple situated in the center of Luxor city. The Temple of Luxor was built largely by Amenhotep III and Ramesses II around 1400BC. Its main purpose was to celebrate the festival of Opet. Many rulers built on to the temple yet it always remained a place of worship for Christians and later Muslims. A mosque built inside the temple still exists and is one of the highlights of the site.
Luxor Temple is beautifully lit at night so it's worth visiting the site at sunset. Hours are 9am - 6pm and admission is 20 Egyptian Pounds. See my article for more information about Luxor, Thebes and Karnak including where to stay and how to get to the major sites.