Located on the northeast coast of Vietnam, Ha Long Bay is one of the most spectacular places I have ever visited. Vịnh Hạ Long, is translated as Descending Dragon Bay.
The bay itself has almost 3,000 limestone islets that pop straight out of the sea, leaving distinct views at every turn. We were able to stay overnight on a Chinese Junk which offered some great shots as we explored the bay. The jagged rocks seem to go on forever into the ocean.
Another interesting area was the Thien Cung grotto caves. Many of the islands are hollow on the inside leaving mysterious passage ways.
As a UNESCO World Heritage Site, Ha Long Bay is a perfect place to relax in Vietnam.
K. Wahlgren 
One of my favourite places when I went to Vietnam! Great pictures!