What year did CERN place the Web in the public domain?

1993 → tub · beam.

On 30 April 1993, CERN released the World Wide Web software into the public domain, royalty-free — arguably the decision that let the Web explode. The Mosaic browser also arrived in 1993. Peg 19 · 93 → tub · beam: a beam of light striking a tub.