Ulu City is based on Singapore, due to the enormous amount of trees in the city Singapore, this might be what becomes of it in the future. It can be accessed from the map "Urban Area 2".
Ulu City also holds the strongest boss of Singapore; Krexel, a huge tree who actually IS the map.
If you die here you respawn in 'Singapore : CBD'.
Singapore : Entrance to Ulu City
Singapore : Ulu Estate I
Singapore : Ulu Estate II
Singapore : Ulu Estate III
Singapore : Along the Ulu City
Singapore : Centre of Ulu City
Singapore : The Destroyed Park I
Singapore : The Destroyed Park II
Other Maps [Singapore]:
Singapore : Remaining Memories of the Ship (Mysterious Path 3 Minidungeon)
See the mobs of Singapore section.