What's with those “The Greatest City In America” benches?

Why do the city’s benches proclaim, \“Baltimore – The Greatest City In America\”?

Baltimore slogans: What story do they tell? - The Baltimore Banner

Baltimore - The Greatest City In America - Charm City Bench : Clothing, Shoes & Jewelry

2910 on the Square - The miniature Baltimore Bench Kit is an ode to the benches found all over Baltimore that proclaim the city's current slogan, the greatest city in America.

Charm City hubris. - American Dirt.

Baltimore Benches The Baltimore Project

Greatest city in america hi-res stock photography and images - Alamy

Baltimore Is the Greatest City In America – Made@Dent

The Greatest City in America - Baltimore

Baltimore; Greatest City in America? That's what the benches tell me. : r/OldPhotosInRealLife

PREORDER The Greatest City in America Bench Slat or Shotski – The Broken Plate Co.

Baltimore Park Bench Line Wall Art Physical Prints 8x8

Baltimore bench - the greatest city in America, Like_the_Grand_Canyon