Heonilleung is a combination of the royal tombs of Joseon dynasty- Heolleung and Illeung. Heolleung is the royal tomb of the 3rd King Taejong of Joseon Dynasty (1367-1422) and his wife Queen Wonkyeong. Illeung is the tombs of the 23rd King Sunjo and his wife Queen Sunwon. Since the royal tombs were completed with 400 years of difference, you can navigate through the tombs and compare the different architect styles of the early and the late Joseon Dynasty.
It's a UNESCO World Heritage and it's located on the east side of Seoul.