After the National Museum of Nature and Science announced Monday that it would start a crowdfunding campaign to help cover its soaring utility costs, it was inundated with donations from the public and at one point its website even became inaccessible.

Museum officials were pleasantly surprised. Donations topped the original target of ¥100 million ($698,000) in just nine hours, and support continues to pour in. As of Wednesday afternoon, over 31,000 citizens had given over ¥500 million through the crowdfunding platform Readyfor.

"I'm surprised at how quickly we were able to raise our funding target, and thankful for the support of so many people," said Kenichi Shinoda, president of the museum, popularly called Kahaku, in a statement on Monday evening.