In order for you to better understand the background stories of each of the characters at City Hall and manage the appearance of your city, version 2.9 of Fortune City presents the new Underlands feature, bringing you brand new areas of the city for you to unlock and explore!
However, before you can begin exploring the Underlands, you'll have to first get to know the Underland Hubs! Underland Hubs allow you to recycle any building in your city (excluding Cashy's statue and the other building as pictured below) in exchange for ore. Once you've accumulated enough ore you'll be able to unlock each of the various Underlands!
If you can't find any Underland Hubs in your city, please see "Why don't I have any Underland Hubs?" or click here to learn more!