Here you can see a pit in closeup. It looks it has a seat in the side, with a hole directly below it? Was this a plughole, or did water come out of it?

Now, if I was to guess what this whole structure was, I would say it was an old spa bath. There are five baths in total. The baths would the extra channels would be hot tubs. The hot water would come in via those channels. The other baths would be cold tubs. So you could just from a hot tub into a cold tub. That sort of thing.

It doesn't explain how they would be emptied. I doubt the ancients had access to flexible hosing. However, it is the best answer I can come up with.

Mystery #2: What is this structure?

Next to the ancient monument, there is a more modern structure. It looks like they used to crush rocks here. There is also evidence that somebody has been squatting in the structure on the left. However, the mattress and blanket look exactly the same as when we first spotted them a few years ago, so I don't think there is anybody living here permanently.

Having satisfied our curiosity we headed back to the track, and down to the beach. The beach is fine for strolling along, but there are much better options available if you fancy a swim. What piqued our curiosity, however, was this old military pill box. What on Earth was it used for? Was it supposed to be buried? No, because part of the structure on the left, has no roof.

Naturally we investigated, and I am happy to report that it didn't swell too much of wee. There were several chambers, none of which had anything of note in them, apart from...

I am guessing that solitary wasps have lived here at some point, though I am happy to be corrected.