I've watched this a few times on Youtube. It's long...7.5 hours...there are parts I love and agree with and parts that I'm not so sure about...but it covers so many very wonderful and interesting topics. There is a verison that has it broken down into like 6 chapters...if you'd rather watch in doses. My fav part is the math involved with Coral Castle--which isn't ancient, but is a "wonder"!!