Kubrick wanted a clear monolith for 2001: A Space Odyssey

Director Stanley Kubrick wanted a transparent monolith for 2001: A Space Odyssey. He asked a UK plastics company to cast one from clear acrylic, but he didn't like the way it looked in a screen test. Instead, he used a monolith made of wood and painted black.

According to Amusing Planet, the unused acrylic monolith [sat unused] in a warehouse for a number of years until an artist acquired it to make a carving for the Queen of England.

The rejected Monolith sat in the Boreham Wood film studios for several years, gathering dust, until famed Slovak-born, London-based sculptor Arthur Fleischmann acquired it. Fleischmann, who pioneered the use of acrylic in sculpture, had received a commission to make glittering crown sculpture for the Queens Silver Jubilee Celebrations in 1977. At two tons, it was the largest block of acrylic ever cast. For three months, Fleischmann patiently chiseled away at the block inside a polythene tent near St. Katherine's Docks, in London. In June the same year, the Queen herself unveiled the sculpture.

The recycled prop has been on public display ever since at St Katherine Docks.