Indeed, in Civ2 and Civ3 (and Civ1, though I haven't played that for AEONS), you could take one or more Ancient and/or Medieval land unit on a pre-Exploration Era ship (even if they had a good chance of sinking in the deep ocean, the point is, you coat hug), and unloading, grabbing goody units (which could increase your war party, give you settlers, or even fully-settled cities), and even mark areas on your map for future cities to send settlers to, and classically go, "a Viking," - a pleasure, ironically, Harold Hardrada in Civ6 is denied by game mechanics.