

Nikon D700 + Nikkor 70-200mm f/2.8 @ 70mm — 1/1000 sec, f/6.3, ISO 200 — map & image data — nearby photos
In Daylight
That's the original of the made-to-look-like-night photo I posted my Dark, Moonless “What am I?” Quiz the other day. Seeing it in its full brightness doesn't make its purpose much more apparent, though.

Nikon D700 + Nikkor 70-200mm f/2.8 @ 120mm — 1/1000 sec, f/6.3, ISO 200 — map & image data — nearby photos
Closer
I just could not figure it out, so I asked the staff at the hotel, who told me that it was a long-closed aquarium. How odd!
It looks like you can just walk onto it to explore, so I asked whether one can walk around, and was told yes, so after checking out, we took a stroll to investigate...

Nikon D700 + Nikkor 70-200mm f/2.8 @ 70mm — 1/2500 sec, f/4, ISO 200 — map & image data — nearby photos
Imposing

Nikon D700 + Nikkor 70-200mm f/2.8 @ 70mm — 1/1600 sec, f/4.5, ISO 200 — map & image data — nearby photos
Ticket Gates
With a faded “Floating Island” above
I wanted to see what the “tank” thing was, so walked up the spiral ramp on the outside, to the second level...

Nikon D700 + Nikkor 24mm f/1.4 — 1/500 sec, f/16, ISO 640 — map & image data — nearby photos
“Touching Pool”
Floating Island Sakaigahama Marine Park
The first guess to my quiz post, by Richard, hit it spot on, even alerting me to a Wikipedia entry on it. It's the main attraction of what used to be “Marine Park Sakaigahama” (with “Sakaigahama” being the name of the area). According to that Wikipedia entry, it opened in 1989, which was the height of the Japanese bubble economy. It closed 10 years later.
Inside the “tank”...

Nikon D700 + Nikkor 24mm f/1.4 — 1/500 sec, f/10, ISO 400 — map & image data — nearby photos
Second Level, Inside
According to the sign, it's the Penguin House...

Nikon D700 + Nikkor 70-200mm f/2.8 @ 70mm — 1/1250 sec, f/2.8, ISO 200 — map & image data — nearby photos
“Penguin House”
Continuing up to the top of the “tank”, we got a nice view of the marina and the hotel beyond.

Nikon D700 + Nikkor 24mm f/1.4 — 1/3200 sec, f/3.2, ISO 200 — map & image data — nearby photos
View from The Island
Bella Vista Hotel on the mountain in the background

Nikon D700 + Nikkor 24mm f/1.4 — 1/500 sec, f/16, ISO 450 — map & image data — nearby photos
Floating Walkway

Nikon D700 + Nikkor 24mm f/1.4 — 1/6400 sec, f/3.2, ISO 200 — map & image data — nearby photos
Greek Vibe

Nikon D700 + Voigtländer 125mm f/2.5 — 1/4000 sec, f/2.5, ISO 200 — map & image data — nearby photos
Synchronized Rusting

Nikon D700 + Voigtländer 125mm f/2.5 — 1/6400 sec, f/2.5, ISO 200 — map & image data — nearby photos
Columns

Nikon D700 + Voigtländer 125mm f/2.5 — 1/3200 sec, f/2.5, ISO 200 — map & image data — nearby photos
Service Window
The place was not deserted... there were some workers doing something involving diving and welding, but they didn't pay us any attention. But it turns out that the place is not just open to the public... a local charter captain came up to let us know that the “do not enter” barrier had been removed so that the workers could enter. It seems that the structure, which is indeed a boat, had sprung a leak that was being repaired.
All the big pools for the animals were mostly under the main platform. I suppose the main platform was for special shows, eating, and other stuff. I like abandoned places (like this) so would have liked to see the whole place, but I didn't feel I could ask, so just chatted as we all walked out.
Thanks for the photo challenge! I never would have guessed that this was an aquarium.
And rather sad that such a nice idea could not work the numbers to stay open. Syncro rusting etc. But it never ceases to amaze me how quickly the plant life (see penguin house) takes back the opportunity to start growing!
Are they going to cut it up and take it away?
Brings a new meaning to the idea of “surplus white goods”
Annie
I doubt they’ll take it away any time soon… it’s been sitting there out of use for 10 years and they’re repairing leaks now. It’s a good breakwater for the marina. —Jeffrey