How to read Korea by dynasty, not by Instagram
Three Kingdoms era (57 BCE to 668 CE) is in Gyeongju (Silla), Gongju/Buyeo (Baekje), and the Goguryeo tomb sites near the DMZ. Goryeo dynasty (918 to 1392) is in Gaeseong (now North Korea) and Ganghwa Island. Joseon (1392 to 1897) is mostly Seoul + Andong + Suwon. Modern (1897 onward) is Incheon's Chinatown and the Demilitarized Zone. Build itineraries by following one dynasty's chain — it produces much better trips than the standard palace-tour rotation.