Dubbed the "Underground First River," it is a rare karst landscape in the Jiangnan region.

Chuiyuntongtian River (located in Tonglu County, Hangzhou, Zhejiang) is a mysterious and magnificent underground karst river, hailed as the "Underground First River." It combines cave wonders, underground river exploration, and cliffside glass walkways, making it a rare karst landscape in the Jiangnan region. Below is a detailed breakdown of its unique scenery and highlights:

1. Core Attractions: Underground River Cave Wonders
- **Boat Ride Through the Kilometer-Long Underground River**
Features: Board a small wooden boat and venture into the deep cave, covering approximately 4.5 kilometers of winding, maze-like waterways with a constant water temperature of 18°C.
Highlights:
- **Stalactite Wonderland**: Stalagmites and stone curtains of various shapes, illuminated by colorful lights, resemble an "Underwater Dragon Palace" (e.g., "Penglai Fairy Island," "Sea-Fixing Needle").
- **Starry Cave Ceiling**: Look up to see firefly-like lights dotting the ceiling, as if traversing the Milky Way.
- **Underground Waterfalls**: Small waterfalls (e.g., "Flying Dragon Falls") form at elevation drops, roaring like thunder.

- **Heart of the Earth Adventure (New Viral Activity)**
How to Play: Wear a helmet and water shoes to hike deep into unexplored primitive cave tributaries.
Thrills:
- **Terraced Calcified Pools**: Milky-white calcified pools stack like natural "terraces."
- **Crystal Walls**: Rock walls embedded with calcite crystals sparkle when lit by flashlights.
- **Ancient Fossils**: Marine fossils from hundreds of millions of years ago can be seen in the rock layers.

2. High-Altitude Experiences: Thrilling Beauty Above the Clouds
- **Lingyun Sky Bridge Glass Walkway**
Location: A 300+ meter-long suspended glass bridge connecting two cliffs, over 150 meters high.
Visual Impact: Beneath your feet lies a lush canyon, with a tributary of the Fuchun River winding like a jade ribbon in the distance.

- **Jiutian Cloud Corridor**
Features: A circular glass viewing platform on the cliff edge, offering 360° panoramic views of forests and villages.
Best Time: After rain clears, when clouds rise beneath your feet, creating a sensation of walking on clouds.

3. Creative Interactions: Blending Light and Nature
- **"Heart of the Earth Expedition" AR Show**: Uses projection technology in the cave to recreate geological evolution, offering an immersive experience.
- **Cave Café**: Sip coffee surrounded by stalactites, embracing the wild charm of a "cave tribe."

4. Nearby Attractions
- **Chuiyuntongtian River + Yaolin Fairyland (15-minute drive)**: Yaolin is famed for its grand scale, while Chuiyuntongtian excels in "boat exploration," making them complementary.
- **Chuiyuntongtian River + Fuchun River Small Three Gorges (40-minute drive)**: Explore the underground river in the morning and cruise the Fuchun River in the afternoon to admire its traditional Chinese painting-like scenery.

5. Practical Tips
- **Tickets**: Combo tickets offer better value (underground river + glass bridge ≈ ¥200; Heart of the Earth Adventure requires a separate ticket, ¥80).
- **Best Season**: Spring, summer, and autumn (June–October for abundant water and cool caves; winter is colder but less crowded).
- **Transport**: 1.5-hour drive from Hangzhou; take a high-speed train to "Tonglu Station" and then a 30-minute taxi.
- **Essentials**: Non-slip shoes for wet caves; spare socks for the Heart of the Earth Adventure (may step in water).
- **Accommodation**: Stay in Tonglu County (more options) or nearby "Daijia Mountain" homestays (secluded mountain retreats).

**Photography Guide**:
- **Caves**: Increase ISO to avoid blur; turn off flash to protect stalactites.
- **Glass Walkway**: Use a wide-angle lens for canyon panoramas; capture sunset rays piercing clouds (Tyndall effect) in the evening.

🌟 **Hidden Gem**:
If time allows, join the cave night tour (holidays only)—explore with just a flashlight after lights-out for an unforgettable experience!

Chuiyuntongtian River perfectly blends "underground adventures" with "cloud walking," showcasing nature’s artistry and human creativity. Ideal for family trips, couple adventures, or photography. Arrive by 8 AM to avoid crowds and fully immerse in this underground wonderland!