“Ocean Dome”, located in Miyazaki, it’s the biggest indoor swimming pool in the world. It’s 300 meters long and 100 meters wide, and it’s located 500 meter from the sea. The temperature inside the pavilion it’s always around 30 degrees and the roof is sky-blue and it has even “clouds”. It has an artificial volcano and also an artificial waves generation system. “Unfortunately” it seems that this world guinness record swimming pool closed this year, I guess they where not making enough money.
Searching on The Net I found this interesting picture. It’s supposed to be the first swimming pool in Japan, almost 100 years ago. Even before the war it seems they already had space problems
Picture from Oldtokyo.com
The biggest outdoor swimming pool is located in Chile, here there are some pictures.