Waitomo glowworm caves: seriously the coldest water I have ever been in and one of the coolest things I have ever done. There are around 300 limestone caves underneath the Waitomo region where hundreds of glowworm lights brighten the caves like stars in the nighttime sky. It was freezing (the water in the caves is never exposed to sunlight), fascinating, and so much fun, particularly when Val led our group in a rendition of Celine Dion's "My Heart Will Go On". Val's no Dion, but she did Titanic proud.