We've all been there: you start researching something, end up with a zillion open tabs, and, for one reason or another, you need to come back to all that later... but you don't want your screen real estate or your precious resources being hogged in the meantime.
There are extensions that can help, like Session Buddy and OneTab, but if all you need is to come back to a session later, that may be overkill. The easiest method is, in fact, built right into Chrome.
It's an often-overlooked feature, but an extremely useful one. OMG! Chrome explains.