Remember Arya on an Icelandic horse riding towards the coast to find a boat to take her to Bravos? The scene was filmed at the top of this waterfall.
Arya rides on an Icelandic horse to the coast in S5 E8 to look for a passage to the Wall in the North. Since the ship is going to Bravos she decides to go there using her half-coin gift from the Faceless Man to negotiate the ride with the ship’s captain.