What looks like rock is actually glass, fiberglass and reinforced concrete.

Among construction innovations there are such materials as iron, steel and reinforced concrete.

The construction materials used were reinforced concrete, glass, and aluminum.

The materials of the buildings are reinforced concrete, glass and aluminum.

The buildings themselves were constructed from stone and reinforced concrete.

The bottom of each module is covered with glass fiber reinforced concrete.

The building is constructed of steel frame and reinforced concrete.

The materials used in construction were steel and reinforced concrete, although the interior is made entirely of stone.

It is very strong once made into steel, and is used to reinforce concrete.

An initial design called for a 12-story building, 120 by 150 feet, reinforced concrete, brick, and steel.

Towards the end of the 19th Century, architects began to use the newer, cheaper materials like metal girders and reinforced concrete to build.

No mention of girders, plastics or reinforced concrete once you step on board.

"Long-time creep and shrinkage tests of plain and reinforced concrete" Proc.

This structure, the first of the second building phase, incorporated reinforced concrete while retaining the forms and materials of the earlier buildings.

The monument is made of steel and reinforced concrete with a lift and viewing gallery at the Cross's arms.

The entire structure was reinforced concrete and was almost as sturdy as it looked.

The mural is made of glass fiber reinforced concrete and is framed with a plain concrete border.

"I picked up iron rods used to reinforce concrete and moved them around eight hours a day," he said.

It is constructed of steel and reinforced concrete and faced with brick.

The entire frame of the building is reinforced concrete and although several minor fires were reported over the years, they were extinguished quickly with minimal damage.