Jupiter and Europa
Jupiter was found to be a dilemma. The largest planet in the solar system would be expected to have seen the largest civilization. On approaching the planet via the moon Europa, extravagant outposts were seen on this moon.
Continuing to the planet's surface, small outposts are found amid the vast oceans. Possibly the larger structures on Europa were meant to scare visitors away.
Rather than evidence of large civilization, even smaller structures are found on the surface. These were determined to be temples. This leads us to assume that population was sparse and widespread in nature, possibly spiritually centered.