Whatever the religion or whoever they're devoted to, shrines have a way of making you contemplative. Visit Jeoldusan Martyrs Shrine and share a quiet moment with the local faithful.
When you've finished exploring this sacred place in Mapo-gu, why not make your way to Gyeongbokgung Palace, Dongdaemun History and Culture Park, and National Museum of Korea? They're near Jeoldusan Martyrs Shrine and also a hit with many travelers.