Note: today's candidate pool was almost entirely YouTube Shorts and hashtag spam, so this is the least-bad pick — but happily it does look like a genuine short-form documentary rather than a vertical Short.

The Li River winds more than eighty kilometers between Guilin and Yangshuo in southern China's Guangxi region, threading through one of the most iconic landscapes on Earth: a forest of steep, isolated limestone peaks known as karst mountains. These formations are the product of hundreds of millions of years of chemical weathering — slightly acidic rainwater slowly dissolving soluble carbonate bedrock, leaving behind the towers, sinkholes, and cave systems that define the region.

The Li River corridor is arguably the world's most famous karst landscape, which is why it appears on the back of China's 20-yuan note and has been painted by Chinese landscape artists for over a thousand years. A short documentary format is well-suited to the subject: enough time to explain the geology and cultural significance without padding, and the aerial and river-level footage tends to do a lot of the teaching on its own.

If you enjoy geology, physical geography, or landscape photography, it's a worthwhile few minutes — and a good primer before diving into longer material on karst topography elsewhere in the world (Vietnam's Ha Long Bay, Slovenia's Kras plateau, the cenotes of the Yucatán).