person A: When my wife and I went to New Zealand last year_comma_ we went swimming at a hot water beach. It was a really fun_comma_ interesting experience.
person B: I've never heard of a hot water beach.  What's it caused by?
person A: There are geothermal springs under the water at that particualr beach_comma_ and they slowly release hot water into the ocean. When the tide is high_comma_ the hot water is carried by the waves onto the shore_comma_ so you get this pleasantly warm water to swim in.
person B: Was that the coolest thing that you did there?
person A: It's really hard to pick the coolest thing we did there. New Zealand is an amazing place_comma_ and there was so much to do. I'd highly recommend going if you get the chance.