With the Portal Reloaded mod, a green portal joins the usual blue and orange ones. It's quite different, though, as it sends you through time---20 years into the future, to be precise.

Science says time travel is possible, but probably not in the way you're thinking. When you purchase through links on our site, we may earn an affiliate commission. Here’s how it works. Is time ...

From H.G. Wells' "The Time Machine to The Time Traveler's Wife" by Audrey Niffenegger and "Outlander" by Diana Gabaldon, time travel has captured our imagination for centuries. The concept is ever ...