A mas­sive wall of vol­canic stones was built by pris­on­ers with no prac­ti­cal pur­pose, serv­ing as pun­ish­ment. The wall stands 8 meters tall and stretch­es over 100 meters. The trail to it pass­es through man­groves, beach­es, and view­points, cre­at­ing a con­trast between nat­ur­al beau­ty and trag­ic his­to­ry.