The most beautiful scenery under heaven is right at Huangshan.
Tips
history
From 《后汉书·胡广传》: the Han emperor An tested officials with written memorials and ranked Hu Guang 天下第一. Already by the Han, the phrase was standard for top-of-the-ranking achievement - a real honorific, not mere boast.
culture
A favorite marketing slogan in Chinese tourism - 天下第一关 (Shanhai Pass), 天下第一泉 (Baotu Spring), 天下第一山 (various candidates). Treat such labels as enthusiastic local branding, not objective rankings.
