Discover the power of collective mourning and the importance of honoring our fallen leaders as we look back at Abraham Lincoln's funeral procession in 1865. This poignant image captures the solemnity of the event and the way that people can come together in times of grief to pay tribute to those who have passed. Read on to learn more about the significance of this historical moment in American history.

Explore the historic use of electric lights during President Woodrow Wilson's 1913 inauguration and what it symbolized for American progress and modernity. Learn how this momentous event marked a new era of hope and optimism, as well as the challenges that lay ahead for the country and the world.

A brazen daylight assassination attempt against President Truman took place right on Pennsylvania Avenue with a shootout in front of Blair House. It was carried out by militant Puerto Rican pro-independence activists. White House Police officer Leslie Coffelt, was killed protecting the President.

This amazing old photograph of the intersection of 14th St. and Pennsylvania Ave., where the Willard Hotel sits, has some amazing details. Click to see them and be blown away!

Take a look back in time with this old photo showing 15th St. and Pennsylvania Ave. in Washington, D.C. in 1931. See the traffic lights and cop gazebo in this vintage image from the Harris & Ewing Collection.

Explore Washington, D.C. in 1919 through this photo of 15th & G Streets near Riggs National Bank. Click to see a larger version and learn more about this historic scene.

This incredibly detailed photo of Pennsylvania tells a story when you zoom in. Read the post to learn more.

A stunning old photo of trucks on parade, going west down Pennsylvania Ave. towards the White House.

On December 28, 1925, a spectacular five-alarm fire broke out in the wholesale candy plant of George J. Mueller on 336 Pennsylvania Avenue NW. It caused $50,000 worth of damage, injured one fireman, and was witnessed by a crowd that overflowed the sidewalks for more than a block. Read this article from The Washington Post for more.

Can you help date this photo of Pennsylvania Avenue and the White House? It appears to be the view down the street from the Capitol Dome, but was not properly labeled. Take a look and see if you can help solve the mystery!

Take a virtual tour of 15th, Pennsylvania and G Streets in Washington, DC with us. We're trying to make out where this is today and could use some help. Check out the Google map and add your ideas in the comments!

Take a look back at Washington, DC's Pennsylvania Avenue in 1925 with this amazing photo. Click to see a much more detailed version. Source: Shorpy.

Take a look back in time to admire the stunning view of Pennsylvania Avenue in the 1920s. See the historical picture from the Library of Congress.

Take a look at this stunning drawing from the 1920s done by Susan Brown Chase. It shows storefronts on Pennsylvania Avenue in Washington D.C. between 22nd and 23rd streets. View the source to learn more!

Explore the fascinating history of Brown's Indian Queen Hotel, a once-stately hotel on Pennsylvania Ave. in D.C. Learn about the hotel's notable guests, historic events and the "Star-Spangled Banner" first sung there in 1814.

Explore the 1901 Inauguration Parade of President McKinley! Learn more about the parade, its participants and a photo of McKinley from the same year riding through the streets of Oakland in this look back in history!

A look at the historic National Hotel, once located at 6th & Pennsylvania Ave. Presidents and duels were plotted there, and John Wilkes Booth stayed there before Lincoln's assassination. The Newseum now stands in its place.

Take a look back at Washington DC's history through a fascinating 1839 print. From lost sheep and cows on Pennsylvania Ave to the bustling metropolis we know today, this print offers a unique glimpse into the past of this iconic city.

Check out these two fascinating old photos from 1913 showing different angles of a traffic stop in Washington DC. The car is a Haynes roadster, which cost about $95,000 today. Don't miss this rare glimpse into the past!

Take a look back in time at three photographs from the 1902 Grand Army of the Republic Parade in Washington DC. See the program of festivities and learn more about the 36th encampment of the Grand Army in Washington.

Explore the Willard Hotel in 1921 through this beautiful photograph taken from the roof of the hotel, featuring an ethereal, almost spectral view of Pennsylvania Avenue at 14th Street NW in Washington.

Get a bird's eye view of Washington, D.C. with this aerial shot of Federal Triangle and the Navy Memorial under construction. Image taken during the 1980s.

Take a trip back in time with this rare painting of the Capitol Building from the early 19th century. Get a glimpse of the Capitol as it looked more than 200 years ago. Source: Library of Congress.

In 1947 (or possibly during WWII), a strange sight occurred on Pennsylvania Avenue: A parade of tanks rolling from the Capitol Building to the White House. Read more to learn why this happened and the discussion on Reddit.

Get an incredible bird's-eye view of Washington, D.C. in 1922! See the Washington Star newspaper building, the Old Post Office, and more. Click now for the full view!

An incredible photograph captures a 7-year-old newsboy trying to sell newspapers in April 1912, the same month as the Titanic's sinking. The caption listed at the Library of Congress is also amusing.

Take a look back in time with this photograph from the Smithsonian archives. Discover history and explore the Renwick Gallery from around 1920.

Take a look at a bird's-eye view of Washington, D.C. from the corner of 18th and Pennsylvania Avenue in the 1920s. This historic image was taken by the Library of Congress.

Take a look at these beautiful photographs of Pennsylvania Avenue in Washington D.C. taken in 1905 by the Rotograph Company. See the eastward, westward, and Treasury Department views down Pennsylvania Avenue.

Take a look back in time with this beautiful photo of Pennsylvania Ave. in the 1920s. We did a little Googling to find this one and came across it here.