A tourist hotspot known for its history and beautiful architecture and its love of water.

以它的歷史和美麗建築物以及對水的熱愛而聞名的旅遊景點。

But while most splash above the surface, below the city is a secret subterranean world.

但是，儘管大多數的景點都在水面上，在城市下方卻是一個秘密的地下世界。

[Caves under the capital]

(神秘的音樂)

Hungary's capital is home to over 80 geothermal springs and dozens of baths, all heated by the Earth's warmth deep below the surface.

匈牙利的首都擁有 80 多個地熱溫泉和數十個溫泉浴場，所有溫泉浴都由地表以下深處的地球溫暖加熱。

As this naturally heated water flowed beneath the city, it carved out hundreds of caves, making the city home to the largest collection of thermal caves in the world.

當這種自然加熱的水在城市下方流動時，它雕刻了數百個洞穴，使這座城市成為世界上最大的熱洞穴集合之地。

The crown jewel of this system is the Molnár János cave.

這裡最著名的是 Molnár János 洞穴。

Discovered in the 19th century by János Molnár, who traced the warm spring waters from the lake outside to its source beneath the city.

János Molnár 於 19 世紀發現這個洞穴，而他從外面的湖泊到城市下方的泉水追溯了溫暖的泉水。

Divers first started to explore the cave in the 1950s.

潛水員於 1950 年代首次開始探索這個洞穴。

Since then, nearly four miles of tunnels have been charted.

從那時起，已經標示了近四英里的隧道。

(gentle music)

(柔和的音樂)

In the pitch black of the cave, miles of rope have been laid for divers to follow the correct route back to the exit.

在洞穴的漆黑中，已鋪設了數英里的繩索，供潛水員沿著正確的路線返回出口。

The water is naturally warm, between 70 and 80 degrees fahrenheit.

水是自然溫暖的，介於 70 至 80 度華氏之間。

The rooms of the cave can range from tiny to massive.

洞穴的空間範圍有微小到巨大的。

The largest is so large, it can hold 350 double decker buses.

最大的洞穴大到可以容納 350 輛雙層巴士。

And even in the pitch black, life has found a way.

在漆黑的環境中，生態也生存下來了。

Biologists have identified new species that live only in these caves.

生物學家已經發現了僅生活在這些洞穴中的新物種。

Much is still to be answered about this place, a reminder that even in the most urban of areas, you can still find some of nature's greatest wonders.

關於這個地方還有很多未知的事情，這也提醒著我們即使在城市最繁華的地區，仍然可以找到一些自然界最偉大的奇觀。