If you really want to learn about Peru, Cusco, and the Incas (as well as other pre-Hispanic civilizations), then you have to do real research from people who have spent much of their actually studying.
I’ve said it many time — if you get your information from YouTube videos then you don’t know much about these topics. Indeed, most of what you’ll learn is probably made up BS with one purpose — making money off of you. (Sorry to disappoint you, but aliens and ancient lost civilizations didn’t build Machu Picchu.)
Fortunately, there are two excellent sources of scholarly publications available on the internet: Academia.edu and Scribd.
I use Academia most of the time. While it is a free platform for sharing academic papers, I found the annual subscription to be extremely worth the cost. (I got it for half price at $49 and have no regrets about the purchase. I’ll renew for the full price as well when the time comes.)
The biggest advantage of the subscription is being able to take advantage of the advanced search functions available. There are literally millions of papers that have been uploaded and the site is used by 120 million academics around the world so being able to narrow down searches is invaluable to me.
The other source I use is Scribd. Here you can find a somewhat different approach to sharing research. You can find all kinds of materials available ranging from books to magazine articles to audio books and even sheet music!
It costs $8.99/month. To be honest I don’t use it nearly as much as I should. The amount of material is tremendous and it is not limited to scholarly materials. Bestselling fiction and non-fiction books are available for download with a membership similar to Kindle books. If you read a lot, it’s more than worth the monthly cost.
I like being able to save titles to my personal library so they show up at the top for quick access when I log in each time. Scribd also has a great iOS app that I use on my iPad.
The links above go straight to Scribd. If you want to subscribe and get 2 free months and help me earn a free month, too, use this link: Scribd Read for Free. The cost is the same for you and you help me out.