That's right - you have a unique chance to sleep in the world's 3rd largest cave. Since first one is in Malasia (Deer Cave) and second (Son Doong in Vietnam) require a week of trekking and $3000 in your wallet, we recommend you Hang En. For under $300. You're welcome.
You'll will have to trek through the jungle and be able to survive two whole days without WiFi. Instead you'll be rewarded with huge cave to sleep (90 meters high) with its own beach and water. A stay to remember forever.
In hotel:
Outside: