Since I am affiliated with the project on the early modern town my family and I strolled through the old Dutch quarters of Semarang on the northern coast of Central Java. Semarang came into Dutch control in 1678. The octagonal Blenduk church dominates this area. It was built in 1753 and is the oldest church in central Java.
There are a plenty of other colonial buildings in this part of the town. I am not sure how old they are.