PillowTalk420

Now the cancer has no escape from it!

Give me a parachute and a machete. I'm willing to brave anything, up to and including nazis, cannibals, poisonous toads, snakes, spiders, giant boulders, and even aliens.

I have heard that there are ruins, possibly Maya or Incan or Aztec (I am not really sure which), that are visible in South America, but have never been explored in (known) modern history.

Is this true, and, if so, why have they not been explored?