The Temple of Jupiter stands in the middle, being the temple of the most important of all gods in the Roman pantheon. It is the largest temple, and deduced from its present, excellent condition, it was the object of first-class engineering.
It is noteworthy that the temple has no entrance by itself, it was entered by bridges across arches from either of the other two temples. As it stands now, the most interesting detail to take in for those climbing the Capitol, are the underground chambers which cannot be entered, but viewed from above.
Jupiter/ís temple has no niche for the god statue. Still there must have been one, probably placed in the middle of the floor. Note the recesses for the roof beams.