Earth is dotted with humongous, human-made structures that, to an alien eye, may be tell-tale signs of intelligent goings-on.

Add Yahoo as a preferred source to see more of our stories on Google. Former U.S. President Barack Obama said he did not see evidence that aliens “have made contact with us,” after sending social ...

Former U.S. President Barack Obama said he did not see evidence that aliens “have made contact with us,” after sending social media abuzz by saying aliens were real on a podcast over the weekend.