A combined team of researchers from Lawrence Livermore National Laboratory in the U.S. and Atomic Weapons Establishment in the U.K. has found that rapidly compressing lead to planetary-core type pressures makes it stronger than steel. In their paper published in the journal Physical Review Letters, the group describes how they managed to compress the metal so strongly without melting it.

Defining strength in a material is difficult. Strength can refer to a material’s ability withstand bending or breaking under certain conditions. Making things even more complicated is that the strength of any given material can change under varying conditions—such as when heat or compression are applied. In this new effort, the researchers showed just how difficult it can be to nail down how strong a material is—in this case, lead.

Lead is not very strong. Pressing a fingernail against a car’s battery terminal is enough to create indentations, for example. But the researchers with this new effort report that the metal can be strengthened considerably by exerting extreme pressure.

In the Marshall Islands, locals have a nickname for the Runit Dome nuclear-waste site: They call it ‘The Tomb’.

The sealed pit contains more than 3.1 million cubic feet (87,800 cubic meters) of radioactive waste, which workers buried there as part of efforts to clean hazardous debris left behind after the US military detonated nuclear bombs on the land.

From 1977 to 1980, around 4,000 US servicemen were tasked with cleaning up the former nuclear testing site of Enewetak Atoll. They scooped up the contaminated soil, along with other radioactive waste materials such as military equipment, concrete, and scrap metal.