It was in fact the discovery of the tomb of Egyptian Pharoah Tutenkhamun, more famously known as King Tut. Archeologist Howard Carter had long suspected the tomb was there to be found, but it took 5 years of searching, at great cost to Lord Carnarvon, a member of the British aristocracy who was his sponsor, before the tomb was found.

What was unique was that it was the only relatively untouched tomb of an Egyptian pharoah ever discovered, all others had long since been plundered by tomb robbers. The tomb was filled with hundreds of items made of gold, including the famous golden mask, golden statues, and golden coffins, which had lain indisturbed and undiscovered for approx 3,500 years.

The mummy's curse was associated with this event, whereby many people associated with the excavation supposedly died mysterious deaths, but most people consider this to be a fanciful myth invented by the mass media to sell newspapers.

A fascinating book on the subject, which I have read a few times, is called Tutenkhamun: The Untold Story, by Thomas Hoving.