Bethell's - Waiti Dunes and Lake Wainamu - Xena film locations
It is a sand Dune - a huge one .
Oh yes, you can climb it. I did! It is kickig when you get on top of it. You are at the edge of a depth and at the top you have the flat black sand.
At the end the Battle took place against the Romans with Bodicea in The Deliverer. The huge dune where Xena came down horse riding in AIST1