Ha Long Bay in north Vietnam, outside of Hanoi is one of the most beautiful places in the world. We lived in south Vietnam for 14 months and saw quite a bit of the entire county but nothing compared to the beauty of Ha Long Bay. It's like something out of science fiction with all the islets rising up out of the water everywhere you look. Do not short yourself and only go for a few hours tour, you MUST go and stay on the over night boats that are converted rice barges. They are beautiful inside and out and the people are so gracious and really understand service. We have a fabulous time, it was only 3 nights but I could have stayed a week.
Make sure you visit the 150 year old floating city, it was truly unique. While we were living there my husband Rick taught English in SaiGon and I volunteered in an orphanage and when the floating city people found out Rick taught English they offered him a job there at the little one room school house, sorry to say there is no way I could live in that small floating environment but it was thrilling to visit.
You can go to a pearl farm and see how they farm the cultured pearls and the process they go though before it is turned into jewellery, of course they have a store where you can buy them too. Out in the centre of the bay there are caves that are some of the largest in the world, the trip to that island is defiantly worth it and I am not even a person who enjoys caves but these were just astoundingly beautiful.
Don't miss going here if you are anywhere new Hanoi, Vietnam you will be glad you did!