Bandar Seri Begawan, Brunei
You might not know about Brunei, the tiny nation that sits atop the split-nation island of Borneo, but it knows about you. Just kidding. The exceptionally wealthy little nation is composed mostly of rainforest, and most of its wealth comes from oil capital.
I only spent three days there, but those three days were enough time to see that the residents are polite and charming, the jungle walks are beautiful, and it's very easy to get lost in a city that feels like a giant theme park. It rained a bit, I sweated a lot, and overall, had a great time exploring a very expensive little slice of jungle.