Land of Romance
From the Super Mario Wiki
The Land of Romance is a moderately sized country in Mushroom World that appeared in The Super Mario Bros. Super Show! episode "Mario and Joliet." The land is under the jurisdiction of various family clans, although Princess Peach is referred to as the "princess" of the Land of Romance and has authority over the heads of these various families. As such, the Land of Romance may be under the control of the Mushroom Kingdom.
The Land of Romance's appearance is quite similar to that of Renaissance times, with several of its buildings resembling structures from that period of time. Aside from a castle belonging to King Koopa and a large church, the bulk of which has been destroyed by Snifits, not many landmarks are shown in the Land of Romance. A large system of tunnels, possibly a sewer, is also present under the Land of Romance.