A large, Howletts-esque cage (that would be a fine enclosure in itself) on a planted island with several large trees. Home to Silvered Langurs ([i]Trachypithecus cristatus[/i]) and possibly the greatest contrast between Saigon and Hanoi - compare this with Hanoi's exhibit for the related [i]T. phayrei crepusculus[/i]:
http://www.zoochat.com/1778/langur-exhibit-hanoi-zoo-15-03-a-269476/