Do you remember the 21st night of September? Chicago Earth, Wind & Fire fans do, as the city has declared it "Earth, Wind & Fire Day."

And now it looks like fans can get a new kind of band memorabilia in Chicago this September.

The Chicago District of the U.S. Postal Service and the City of Chicago will pay a tribute to the Chicago-bred, multi-platinum, international superstars as they unveil a USPS pictorial postmark in honor of the band Saturday, also dubbed “Earth, Wind & Fire Day.”

“For more than 40 years, a band that grew out of Chicago’s rich musical tradition has thrilled millions with its uplifting songs and spectacular performances,” Chicago District Manager and Postmaster Karen Schenck said in a statement. “We are honored to come together with the city to recognized Earth, Wind & Fire.”

The postmark was designed by Chicago-based artist Nicolosi and is the most recent in a series of numerous commemorative artworks created for the USPS.

Co-founder of the band and bassist Verdine White will attend the unveiling and will autograph USPS commemorative cache envelopes as well as the band’s new album “Now, Then & Forever. “

“September is Earth, Wind & Fire’s number one most requested hit song of all time,” White said. “Mayor Rahm Emanuel’s proclamation and the USPS postmark, designed by Nicolosi, is a major milestone for Earth, Wind & Fire.”

The event will be held at 10 a.m. at the Garfield Park Conservatory, 300 North Central Park Avenue.

