The Expo Park in Suita City, Osaka Prefecture, is hosting a firefly-viewing festival through June 12.

The annual festival gives visitors to this sprawling park of 260 hectares a rare chance to view up to 240 fireflies in the Japanese Garden section of the park.

Fireflies, which prefer a clean, unpolluted environment, are becoming harder to spot in Japan. At the park, two kinds of Japanese fireflies — genji-hotaru and heike-hotaru — can be seen at night.

Volunteer guides will explain the biology of the winged insects in Japanese, while street performers will entertain visitors with juggling and dancing shows nightly. Street vendors will be there Saturday and Sunday, and some products from Shiso, Hyogo Prefecture, will be on sale.

The park was created on the former site of the Japan 1970 World Exposition, in commemoration of the fair's huge success. Among the many attractions are the 70-meter-tall Tower of the Sun, the symbol of the expo created by late-artist Taro Okamoto, and the National Museum of Ethnology, where exhibits and information regarding every ethnic group in the world are collected and displayed. The park also houses the International Institute for Children's Literature, which houses some 650,000 books, magazines and other collected materials.

The park is open during the festival until 9:30 p.m., but its entrance gate closes at 9 p.m. The festival will be canceled if it rains. Admission is ¥250 for adults and ¥70 for elementary school and junior high school students. For details, call (06) 6877-7387 or visit www.osaka-info.jp/en/search/detail/event_7552.html.