A Japanese city boasting one of the world's largest hot-spring resorts opened a special amusement park on Saturday with a hot-tub merry-go-round and other rides featuring immersion in its famous thermal water.

The "spamusement park" will operate for just three days at an existing amusement park in Beppu, Oita Prefecture, after the southwestern Japan city successfully raised funds to set up special rides featuring the local hot-spring water.

The attraction became a reality after Beppu Mayor Yasuhiro Nagano committed to open such a park in a YouTube video uploaded last November. The local representative pledged to go through with the idea if the video got more than 1 million views, a goal achieved in just three days.

The video's conceptual footage showed men and women of all ages wrapped in towels having fun at a park combining bathing and rides, which was originally an idea to promote tourism in the city.

The roller-coaster was depicted in the video as having seats filled with hot water, but the city opted to use bubbles made from hot-spring ingredients instead of water, due to safety concerns.

"I got so excited. This is something extraordinary you can experience only here," said visitor Yuko Akagi, 28, after riding the roller-coaster.

Wrapping her bathing suit-clad body with a towel, she said the bubbles felt nice. "I felt refreshed," said Akagi, who lives in Beppu.

The city, which crowdfunded about 82 million yen ($740,000) for the project, is letting only those who donated a certain amount of money enter. About 12,000 people are expected to ride the park's eight attractions in the three days it is operating, city officials said.