take in all the sights — meaning?

Question

Source: http://www.examiner.com/article/ufo-spotted-above-the-moon-s-surface-explorers-from-another-planet-video

Back in 1968 a photo from an old lunar orbiter caught the image of a spaceship tucked into the bottom of the moon’s Manilius Crater. That was over four decades ago, so seeing UFOs on the moon and scoping the moon out from above is nothing new.

If Earth can visit Mars and take in all the sights, why can’t a planet be checking out the moon? Maybe they are checking out the Earth from a hidden observation point on the moon and the periodic reports of UFOs on or flying over the moon stem from this?

I'm not sure what that means. Please help me.

Answer 1

From Vocabulary.com's article on sight:

You can "take in the sights," meaning you're seeing all the special attractions of a town (also known as sightseeing).

The authors say that Earth's nations send probes, satellites, landers to Mars to explore every possible feature, capture every important bit of landscape. "Take in all the sights", in short. They compare these robotic and automatic vehicles to tourists, because it's tourists who usually try to capture all the sights on their cameras.