Diatoms
Diatoms are unicellular algae that have a unique glass-like wall made of hydrated silica (silicon dioxide) embedded in an organic matrix. The wall consists of two parts that overlap like a shoe box and its lid. These walls provide effective protection from the crushing jaws of predators: In 2003, researchers in Germany found that live diatoms can withstand pressures as great as 1.4 million kg/m2, equal to the pressure under each leg of a table supporting an elephant! Much of the diatoms' strength comes from the delicate lacework of holes and grooves in their walls; if the walls were smooth, it would take 60% less force to crush them.