Pasieka Bakery has served the Avondale neighborhood for more than 75 years.
It took 150 firefighters nearly four hours to put out the fire, which included several hidden fires in the building, at 3056 N. Milwaukee Avenue near Lawndale.
"The fire was extremely difficult to get. It was in the ceilings above the oven and ijt extended into the two story into the walls," said Commissioner Robert Hoff, Chicago Fire Department.
"It looked like the front of the store might be intact and the rear has to be re-done completely. I am hoping to God they can put it back together because it is a gemstone in our community," said Ald. Ariel Reboyras, 30th Ward.
Pasieka Bakery has been an important fixture in the community since the 1930s.
"The most famous visitor was a picture that cataloged Secretary of State and former First Lady Hillary Clinton," said Daniel Pogorzelski, Northwest Side Chicago Historical Society.
"I remember when I was 4 or 5, I would come here with my parents. We'd come and get pastries and cookies, and they had beautiful glass, curved glass displays," said Robert Groszek, Greater Avondale Chamber of Commerce.
Residents say the bakery was not a landmark but represented an important part of architectural history. Jacob Kaplan, editor of Forgotten Chicago magazine, said the front window of the bakery was art deco.
"During the depression, there was tax credits and mortgage-backed loans by the federal government to modernize storefronts. This is clearly an example of a business taking advantage of that...This is one of the best preserved examples up till today of that style of storefront modernization in the city," said Kaplan.
"It is a neighborhood institution and landmark both for Polish Chicago and for people who just like to come in and explore Warsaw a little closer to home," said Pogorzelski.
The cause of the fire is still under investigation.