The hills, due to their complexity and position form a barrier between the two countries.

The hills and rivers of Pittsburgh form many barriers to transportation within the city.

The hills were quite flat on the top, forming a kind of plateau overlooking the airport.

The hills form a valley, which constitutes an extension of a wadi.

The Chalk is less easily eroded so forms the only significant hills in the county.

In front of them, the hills formed an impenetrable line.

An artificial hill and a grotto also form part of the gardens.

The hills form the central part of the Satpura Range.

The hills form a large horseshoe shape with its open end facing west.

The bay is one of traditional fishery port because the hills on two sides forms a nature shelter.