(cokada/iStock/Getty Images) Alien megastructures built to harvest stellar energy or alter the orbits of stars may be ...

If you’re trying to come up with the best game plan for proving the existence of extraterrestrials, you’ve got plenty of options. Naturally, you want a strategy with a high chance of success, simply ...

From the longest tunnel of the ancient world to a highway suspended above raging waters, Rome built engineering marvels that ...