A third pylon leads on to the oldest parts of the temple, past obelisks added at the behest of Pharaoh Seti I and Queen Hatshepsut in the New Kingdom era.
The second pylon leads to the oldest part of the temple. 
mnli hypothesis: The second pylon leads to the oldest part of the temple.  premise: A third pylon leads on to the oldest parts of the temple, past obelisks added at the behest of Pharaoh Seti I and Queen Hatshepsut in the New Kingdom era.