Unknown Horizons is an open-source real-time colony-building economic simulation and strategy game, loosely based on the game "Anno 1602"/ "1602 A.D."
As usual in this type of game, you start off with few people or resources: it's just you, your trusty ship and a cluster of nearby islands. This unhappy situation doesn't have to last for every long, though, because in very little time you can build cities on the islands and begin to make money.
Much of the game is about how you manage these cities. You'll need the right balance of residential areas and industrial estates, for instance, while organising your resources to ensure that everyone gets fed and you've room for growth.
But of course you're not alone. There are indigenous people on the islands, as well as competitors busily building their own empires. You can take the peaceful route, trade with them, negotiate non-aggression pacts for the greater good... Or you might prefer to kill them all. It's really your call.
And while you're juggling all that, don't forget to keep exploring, find new islands with valuable resource deposits before your neighbours do: it could be the difference between defeat and victory.