Here's a new #mysteryphoto Boston! Do you know where and when this photo was taken?

September 15th - October 15th is Latinx Heritage Month! Take a look at this City Council Resolution recognizing it below! #LatinxHeritageMonth #NationalHispanicHeritageMonth

Today we honor and remember all those who lost their lives on September 11, 2001.

It's time for another #mysteryphoto! Can you figure out where and when this photo was taken?

Happy first day of school to all BPS students! #BostonPublicSchools Image: Dorchester High School science class, circa 1901.

Happy Labor Day, Boston! In 1889, a championship rowing regatta was held on the Charles River! How will you celebrate today?

It's #mysteryphoto time! Do you know where and when this photo was taken?

The Tremont Street Subway, the first subway in the United States, opened in Boston #onthisday in 1897! Check out photos of the subway cars! Image 1: First car in subway for public service, September 1, 1897 Image 2: Open summer cars at the Public Garden entrance to the subway, September 1, 1897

It's #mysteryphoto time! Can you figure out where and when this photo was taken?

Here's a new #mysteryphoto for you, Boston! Can you figure out where and when this photo was taken?

Check out the corner of East Fourth and K Streets #onthisday in 1897!

It's time for another #mysteryphoto! Do you know where and when this was taken?

Take a look at Commonwealth Avenue in Brighton #onthisday in 1927!

Here's a new #mysteryphoto for you, Boston! Do you know where and when this photo was taken?

Take a look at Copley Square photographed #onthisday in 1914!

It's #mysteryphoto time! Do you know when and where this was taken?

Check out the corner of Summer and Kingston Streets #onthisday in 1903!

It's time for another #mysteryphoto! Can you figure out where and when this photo was taken?

Happy 87th birthday to former mayor Raymond L. Flynn! Image 1: Mayor Raymond L. Flynn in his office Image 2: Mayor Raymond L. Flynn running Image 3: Mayor Raymond L. Flynn playing baseball

Take a look at the Boylston Street subway entrance near the Public Garden #onthisday in 1915!

Here's a new #mysteryphoto for you Boston! Can you figure out when and where this photo was taken?

As the tall ships get ready to leave port, we are looking back on some memories from Operation Sail Boston in 1976!

Check out construction work at Forest Hills #onthisday in 1908!

Check out Dover Street Station on the Elevated Railway #onthisday in 1959!

It's #mysteryphoto time! Do you know where and when this photo was taken?

250 years ago today, the Continental Congress adopted the Declaration of Independence! Check out these tickets and programs from celebrations in 1876! #Boston250 Image 1: Anniversary Exercises ticket Image 2: Evening Concert ticket Image 3: Anniversary Exercises program Image: 4: Timber Races flyer

It's time for another #mysteryphoto! Can you figure out where and when this photo was taken?

Take a look at the Charlestown Navy #onthisday in 1901!

Here's a new mystery photo for you, Boston! Can you figure out where and when this photo was taken?

Check out Atlantic Avenue at Rowes Wharf #onthisday in 1942!