Li River, China
We took a 3rd class 30 hour trip from Shanghai to Guilin in an effort to save money. We were right next to the toilets and everyone on the train was chain-smoking. By the time we made it to Guilin, all three of us were sick. We were hacking up our lungs on our boat journey to Yangshuo but started to feel a lot better when started approaching these crazy karst mountains jutting out of the Li River.