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.
This list of longest tunnels in the world ranks tunnels that are at least 13 km (43,000 ft) long. Only continuous tunnels are included; pipelines (also buried) are excluded. The longest have been constructed for water distribution, followed by tunnels for railways. Both uses are highly sensitive to gradients.