After banking 50 Jiggies this globe will be available. Again retrieve it from L.O.G. and drive to the back of "Uptown" (a circle of houses with a large gated section in the middle) and drive underneath (press B to submerge). The globe will stay behind and float, but once you get inside you will find a switch. Use the switch to lower the water and then go back to get the globe. Now drive up inside the gated section of Uptown to find this plinth.
Note: The Scuba Gear is required to enter the secret tunnel so you will need to complete the Grunty battle of the Jiggoseum first.