In order to reach Travincal, you must first make it to Upper Kurast (Waypoint). You can get there from Level 1 of The Sewers or by traveling past Kurast Bazaar. Make your way north until you pass the Kurast Causeway and reach Travincal. Make sure to set a Waypoint, the Council Members are dangerous and you'll have to defeat one of them to obtain Khalim's Flail.