Found via the digital information systems installed at many subway stations in Seoul, I traveled to the Amsa Prehistoric Settlement, a recreation of life in the Neolithic Era, also known as the pre-Kimchi age. Prehistoric settlements were actually excavated in that area, though the buildings you can see are recreations of course.
Besides the buildings, ancient earthenware and weaponry are presented in the exhibition halls along with information about life during that time.
There is not much else interesting in that area, but Samseong Station (COEX Mall, Bongeunsa Temple) is only a short subway ride away.
The nearest subway station is Amsa Station on line 8. Admission fee is 500 Won for adults and 300 Won for kids. It’s closed on Monday and New Year’s Day, but open on national holidays. Amsa is the last stop on line 8, line 8 connects to line 2 (green line) at Jamsil and line 5 at Cheonho.