In Search Of... "Earth Visitors" (1980)
This rather interesting episode starts off with Leonard Nimoy talking about burros and how they were left in Death Valley where you'd think they'd die but instead they multiplied after adjusting to the area. This episode then takes a look at the possibility that aliens visited Earth thousands of years ago and accidentally left a person or two, which then multiplied to what we are today. There are several different theories thrown around and I must admit that I found them all to be fascinating including questions about how Indians got to America and why they had certain beliefs that wouldn't become proved until the 1960s. If you're a fan of the series or this type of information then you'll certainly enjoy this.
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