Hey guys, I just watched this video about guys cycling across the world, and I was wondering whether they had to get visas for every country they passed through.

They're Germans, so they could get through Europe without any additional visas, but in this video (https://www.youtube.com/watch?v=fL-yvu10LqU) [Embed] they ride all the way to India.

If someone could answer this for me, I'd be grateful. Visas are a pain in the ass so avoiding them is a win in my book.
Yes, this was originally posted on /trv/, but I figured that you guys might have some good insight too.