Located in Yishui county, Linyi city, Shandong province, the Firefly Stream Cave & Underground Grand Canyon Scenic Area is a national 5A-level tourist destination. Comprising two major attractions—the Firefly Stream Cave and the Underground Grand Canyon—it offers a rich blend of leisure sightseeing, eco-tourism, and scientific exploration.

Firefly Stream Cave

The Firefly Stream Cave is renowned for its firefly displays, rare in Asia; its diverse stalactite formations; and its expansive ecological Butterfly Valley, one of the largest of its kind in regions north of the Yangtze River. With a year-round temperature ranging from 17°C to 20°C, the cave offers a mysterious yet serene environment. Inside, tens of thousands of fireflies illuminate the cavern ceiling like stars twinkling in a clear night sky, creating a mesmerizing spectacle. Visitors glide through the darkness on rope-drawn boats, immersing themselves in a fairytale world aglow with "starlight."

Nestled between mountains and a lake, the Butterfly Valley features lush vegetation threaded by a gentle stream. It is home to tens of thousands of colorful butterflies, including more than 50 well-known species such as Sericinus montela, Kallima inachus, and Byasa. With small bridges, flowing water, secluded valleys, blooming flowers, fluttering butterflies, and pristine greenery, the valley forms a tranquil and idyllic retreat.

Underground Grand Canyon

The Underground Grand Canyon is a dramatic karst cave system plunging nearly 100 meters deep, with sheer, cliff-like walls. Its passages range from wide corridors once capable of accommodating carriages to narrow stretches allowing only single-file passage. The cave features striking stalactite formations and notable sights such as the "one river," "nine springs," "nine palaces," "twelve waterfalls," and "twelve gorges." Extending 6,100 meters, the underground river offers an exhilarating rafting experience that showcases the area's raw, untamed beauty, making it a favorite among visitors.

Location:

Firefly Stream Cave: Simendong village, Dongtou town, Yishui county, Linyi city, Shandong province

Underground Grand Canyon: Yongfuzhuang village, Dongtou town, Yishui county, Linyi city, Shandong province