Do you mean visually beautiful or thematically beautiful?
For the former, I've always held Square Enix's games as beautiful. Final Fantasy XII has some breathtakingly beautiful environments in it, as does Final Fantasy X, even with it's dated graphics. Xenoblade Chronicles is also a rather visually stunning game.
For the latter, Bastion is my go-to answer. It's atmospheric, well paced, the difficulty is fair, and the end of the final area is one of the most thematically beautiful moments I've had the pleasure of experiencing. And it also fits into the former category to boot!
For the former, I've always held Square Enix's games as beautiful. Final Fantasy XII has some breathtakingly beautiful environments in it, as does Final Fantasy X, even with it's dated graphics. Xenoblade Chronicles is also a rather visually stunning game.
For the latter, Bastion is my go-to answer. It's atmospheric, well paced, the difficulty is fair, and the end of the final area is one of the most thematically beautiful moments I've had the pleasure of experiencing. And it also fits into the former category to boot!