This place freaked me out. The is Burncoat Head Park in Nova Scotia, site of the world’s highest tides, with an average tide of 47.5 feet and as much as 53.6 feet. Depending on the time of day, this entire basin can be filled with water up to the green line, or as empty as you see it here. 

We timed our visit to have plenty of time to explore, but I confess the entire experience was extremely unsettling.  I was not afraid that a wall of water would come rushing it, but I think I somehow sensed that I was standing on ground that is essentially also an ocean bottom, and it just felt completely unnatural to be standing there.