A "showpiece event" is a term used to describe a highly significant, impressive or grand occasion that is meant to showcase or display something outstanding, often for promotional or entertainment purposes. Full definition
At the grand LG G3 Day showpiece event in London, the new tablets were on show and so we got chance to spend a little time taking a look at each of them. (androidcentral.com)
To date, he has one Copa del Rey and could win another this weekend as Luis Enrique's side take on Sevilla in the Spanish showpiece event. (caughtoffside.com)
The game would reportedly take place on 7th June, with the South American showpiece event starting in Chile four days later on 11th June. (caughtoffside.com)