Gamma rays are the least powerful but can penetrate through even thick concrete.

They had to be transported from the plant in lead-lined coffins and buried under thick concrete.

Old though it was, the crypt looked quite new, for its floor was composed of thick concrete.

The walls, ceiling and floor are all two-foot thick steel-reinforced concrete.

In addition, homes are often built with thick concrete or stone walls and reinforced roofs.

Cavity wall types have an inner leaf of at least 100-125mm thick concrete.

Feet planted wide, he regarded the thick concrete with pleasure.

The guns were not put out of action by bombing despite being hit many times, due to the thick concrete.

The floor of the service catwalk is 100mm thick concrete as ballast to resist wind uplift.

Everything important or vital was on the bottom floor, Level Three, protected by thick concrete and other, less obvious measures.