contain substantial fraction(at least 30%) of gravel-sized particles; have ROUNDED clasts,closely related to sandstones in terms of origin and depositional mechanisms what kind of sedimentary structures do conglomerates usually have?
The underground Disney tunnels are the center of activity for the Cast Members and the operations of the park. There are color coded signs to help Cast Members find their way around. They travel around in electrical powered vehicles which look something like golf carts.
Tunnels provide some of the last available space for cars and trains, water and sewage, even power and communication lines. Today, it's safe to bore through mountains and burrow beneath oceans -- but it was not always this way. In fact, it took engineers thousands of years to perfect the art of digging tunnels.