On this day 28 January 1958 Lego Bricks patented

The basic plastic bricks
 
From Wikipedia:

"The Lego Group began in the workshop of Ole Kirk Christiansen (1891–1958), a carpenter from Billund, Denmark, who began making wooden toys in 1932. In 1934, his company came to be called "Lego", derived from the Danish phrase leg godt, which means "play well". In 1947, Lego expanded to begin producing plastic toys.  
By 1954, Christiansen's son, Godtfred, had become the junior managing director of the Lego Group. It was his conversation with an overseas buyer that led to the idea of a toy system. Godtfred saw the immense potential in Lego bricks to become a system for creative play, but the bricks still had some problems from a technical standpoint: their locking ability was limited and they were not versatile. In 1958, the modern brick design was developed; it took five years to find the right material for it, ABS (acrylonitrile butadiene styrene) polymer. The modern Lego brick design was patented on 28 January 1958."

Lego from plastic to Metal!