Banten Lama, Indonesia. Image © Mike Aquino, licensed to About.com
Southeast Asia has long been an attractive target for conquerors. When the area's powers weren't conquering each other, Europeans were constantly romping through the area, picking up stray colonies when the local kings weren't looking.
The Khmer, Vietnamese Nguyen royalty, Majapahit, Sri-Vijayan, Spanish, Dutch, Portuguese and British conquerors may not have been able to hang on to the present day, but their structures have. Learn more in our list of Ancient Fortresses in Southeast Asia. A related list of structures can be found in this list of UNESCO World Heritage sites in Southeast Asia.