The stupa (aka the chorten or the pagoda) is Buddhism's universal piece of symbolic architecture. Borobodur in Java is probably the most famous, while Burma's Shwedagon Pagoda is the largest, and the Kyaik-htiyo Pagoda on the Golden Rock may be the most precarious. They're common across the Himalayas, and sometimes hidden in caves.
Dunhuang Art. Buddhist cave art and history.
The International Dunhuang Project, developed jointly by the British Library and the National Library of China, makes thousands manuscripts and paintings from ancient caves and temples along the Silk Road viewable to the public. The artifacts were found in the Dunhuang cave in China in 1900 and dispersed to museums around the world, but now they have been brought together on the web. And if you want some appropriate music to go with it, check out Yo Yo Ma's Silk Road Project.