Tiahuanaco, one of the oldest ruins on earth, and here you have the Gateway of the Sun:
Now just imagine for a second, what they used that for, and consider where have all these lost civilizations just gone, disappeared.
Notice the empty block spaces on the sides of the gate, imagine if those were for vital components, which were removed, say, resonating crystals.
Theres your stargate right there, and this was there far longer and before any idea of a stargate for TV show or a book.
All these sci-fi shows have great truths in the stories, just dont let it stereotype the truth as fiction, because thats what some people intend with these productions, and others are hoping people will catch on to the truth.
Peace