NEW YORK -- Eagle-eyed folks on Twitter on Monday spotted a subtle change to the Mets' skyline logo on the team's social media accounts. And Twitter exploded.

On the right side of the skyline, the UN Headquarters appeared to be replaced by the Citigroup Center, with its distinctively slanted roof. Of course, the UN is a peace-seeking institution and city landmark. Citi is the Mets' signature sponsor, paying $25 million a season for naming rights to the stadium.

On Tuesday, a Mets official told ESPNNewYork.com that the official logo is not dropping the UN Headquarters. The Mets' social media accounts have reverted to the standard logo. The official did not respond to a follow-up inquiry about why the Citigroup Center-incorporated logo apparently was used on the social-media accounts.

The logo debuted on Nov. 16, 1961 and has gone "virtually unchanged," according to the Mets.

Notice after 53 years the Mets changed their logo. That is the Citigroup building in place of the UN. pic.twitter.com/JdKkWEcTdM — Ed Anderson (@AndersonEd27) September 16, 2014

Read more at Uni Watch.