Lisa Wardle | lwardle@pennlive.com

Back in the early 20th century, Pittsburgh was a drastically different city. It was dirty but more populous. It had different bridges and roadways. And many of today's landmarks hadn't even been built.

We compared recent photographs with those from the 1920s and 1930s to see how each area has changed in the past century.

Here is a look at the different regions.

Don't Edit

The Point and the North Side as seen in 1930. (Courtesy of Archives Service Center/University of Pittsburgh)

The Point then

The Point was an industrial zone through the early 1900s due to its convenient location at the confluence of three rivers. The area deteriorated to a slum in the 1940s.

In 1945, the development of a park was authorized. It took until 1974 for all parcels to be purchased and transformed into what we now know as Point State Park. The park gained national historic landmark status in 1975.

Manchester Bridge (left of the Point) and Point Bridge (right) were demolished in 1970, but their stone supports remain today, largely blended into the scenery.

On the left side of the image, the North Side appears relatively empty without current landmarks like PNC Park. The Pirates left the North Side in 1909 to play at Forbes Field in Oakland until 1970. They returned to the area when Three Rivers Stadium opened, then moved to PNC Park in 2001.

Don't Edit

The Point as seen on July 12, 1932. (Courtesy of Archives Service Center/University of Pittsburgh)

Don't Edit

The Point and the North Side as seen on April 18, 2017. (Barry Reeger | Special to PennLive)

The Point now

Point State Park has more breathing room than its former life with new bridges pushed toward downtown and plenty of green space. Markers and plaques in the park recognize its historic value from when the English and French fought over the region.

Granite outlines within Point State Park show the river's edge as it was in the mid-1700s, as well as the location of Fort Duquesne and four of the five bastions of Fort Pitt.

Don't Edit

The Point and the North Side as seen on April 18, 2017. (Barry Reeger | Special to PennLive)

Don't Edit

Don't Edit

The Monongahela River as seen in 1930. (Courtesy of Archives Service Center/University of Pittsburgh)

Monongahela River then

Allegheny County erected 99 bridges between 1924 and 1932. Among that class of bridges was the West End Bridge, the Point Bridge and the Liberty Bridge.

Spanning the Ohio River in the top left is the West End Bridge, which was under construction at the time of this photograph. It carries U.S. Route 19 and was completed in 1932 by the American Bridge Company of New York.

Just below, at the end of the Monongahela River, is the second version of Point Bridge, built from 1925-1927 to replace one that had existed in the area since 1877. The bridge closed in 1959 but was not demolished until 1970 with development of Point State Park.

The Wabash Bridge was completed in 1902 to carry the Wabash-Pittsburg Terminal Railroad into the city. Just one year after completion, the bridge collapsed. It was replaced in 1904, and the first train on the span took riders to the World's Fair in St. Louis. The rail company went bankrupt in 1908. The bridge was removed in 1948.

The Smithfield Street Bridge is the oldest river bridge still standing in the city, having opened in 1883 under the hands of famed bridge designer Gustav Lindenthal. The bridge originally had a single lane but was widened in 1891.

The Panhandle Railroad Bridge was completed in 1903 to carry the railroad across the river. It is now used for the Port Authority T Line.

The Liberty Bridge was built locally by the Independent Bridge Company and opened in 1928. At the time, it was the longest and most expensive bridge in the county, costing $3.7 million.

Don't Edit

The Monongahela River and downtown as seen on April 18, 2017. (Barry Reeger | Special to PennLive)

Monongahela River now

The river looks mostly the same as it did 80 years ago, though the bridges have changed.

At the top of the photograph spanning the Ohio River is the West End Bridge, completed in 1932.

Moving down to the Monongahela River, the first bridge, reaching Point State Park is the Fort Pitt Bridge. The span was completed in 1959, just one year before the connecting Fort Pitt Tunnel opened.

The Smithfield Street Bridge, Panhandle Railroad Bridge and Liberty Bridge all remain largely unchanged from the early 20th century.

The 10th Street Bridge was built in 1933. It is the only cable suspension bridge crossing Pittsburgh's three rivers, though it appears quite similar to the Three Sisters bridges on the Allegheny, which use eye bars for reinforcement.

Don't Edit

Oakland as seen in 1923. (Courtesy of Archives Service Center/University of Pittsburgh)

Oakland then

Andrew Carnegie donated $1 million to the city to establish the Carnegie Technical Schools in 1900. It catered to the working class but began to offer degrees after a few years. Still, the campus did not grow much until after World War II.

University of Pittsburgh, though established in 1787, did not have any Oakland buildings until 1908. A fundraiser for the Cathedral of Learning in 1925 allowed children to "buy a brick" for 10 cents. The building was dedicated in 1937.

Don't Edit

Oakland as seen in 1930. (Courtesy of Archives Service Center/University of Pittsburgh)

Don't Edit

Oakland as seen on April 18, 2017. (Barry Reeger | Special to PennLive)

Oakland now

The University of Pittsburgh and Carnegie Mellon University campuses have expanded significantly in the past 80 years.

Pitt's original layout was meant to include 30 buildings mimicking Green and Roman temples on the hillside. Only five of those structures were built before a new chancellor switched gears and turned all effort to creating the grand Cathedral of Learning. A mishmash of architectural styles followed on the hillside and central Oakland in the following decades.

When Forbes Field met its end in the 1960s, Pitt again had the opportunity to expand its lower campus with new halls and the Barco Law Building, among other structures.

Meanwhile, the Carnegie Institute of Technology in 1948 established a major addition with what's now called the David A. Tepper School of Business. In 1967, the university merged with the Mellon Institute and established schools to focus on science and humanities. The H. John Heinz III College for public affairs arose in 1968 and the School of Computer Science came in 1986.

Don't Edit

Don't Edit

Oakland and Schenley Park as seen on April 18, 2017. (Barry Reeger | Special to PennLive)

Don't Edit

Downtown, the Hill District and the Strip District as seen on Sept. 20, 1931. (Courtesy of Archives Service Center/University of Pittsburgh)

The Hill District then

The 1930s was part of the golden era of the Hill District. Immigrants poured into Pittsburgh for work in the early 20th century, with the majority of African-Americans settling in the Hill District. They brought their culture along and established their own entertainment for a city within the city.

Jazz was alive in "Little Harlem," which became the hot spot between New York and Chicago. It took a few more years before establishments like the Crawford Grill and New Grenada Theater hit full swing in the mid-1930s.

In 1931, the year this photo was taken, construction began on America's first black-owned and black-built baseball park, Gus Greenlee Field, named after the bootlegger and numbers runner who established the new Negro National League. It was home to Greenlee's Pittsburgh Crawfords, which won three league titles from 1932 to 1936.

Don't Edit

An aerial view of the Hill District as seen on April 18, 2017. (Barry Reeger | Special to PennLive)

The Hill District now

In the 1950s, the city demolished the Lower Hill to make room for the Civic Arena and a cultural district, which never came to fruition. The decision displaced more than 8,000 residents.

Pittsburgh established public housing complexes in the area and through the next few decades razed dilapidated buildings instead of rebuilding them.

Now, the Hill District is working to re-establish itself. Community groups and nonprofits got the area a new library in 2008, followed by a YMCA facility, bank branches, grocery store and more.

Work is also moving ahead with the former Civic Arena site, which the Penguins and developer McCormack Baron Salazar hope to turn into a 1,000-unit residential development.

Don't Edit

Downtown Pittsburgh as seen on Oct. 5, 1930. (Courtesy of Archives Service Center/University of Pittsburgh)

Downtown then

Historic Market Square was part of the city's layout since George Woods and Thomas Vickroy first drew the grid in 1784. Though difficult to see at this angle, it served as the New Diamond Market from 1914-1961. Instead of an open-air market, the quadrant held twin structures that allowed Diamond Street (now Forbes Avenue) to pass underneath and intersect with Market Street.

Fourth Avenue was also on the original grid and became known as the city's Wall Street during the 19th century. The street contains historic structures today built during the booming business industry in the late 1800s and early 1900s. Examples include Dollar Bank (1870) and the Point Park University Center, which formerly held the Colonial Trust Co. (1902).

The Grant Building was new at the time of this photograph. To this day, its beacon continues to flash the city's name in Morse code ... except for the time it instead spelled "Pitetsbkrrh."

Don't Edit

Downtown as seen on July 12, 1932. (Courtesy of Archives Service Center/University of Pittsburgh)

Don't Edit

Don't Edit

Downtown Pittsburgh as seen on April 18, 2017. (Barry Reeger | Special to PennLive)

Downtown now

As businesses came and went, so changed downtown Pittsburgh.

Numerous landmarks were constructed during Pittsburgh's renaissance from 1946-1974 thanks to financier Richard Mellon and Mayor David L. Lawrence. Buildings from this era showcase materials the city was known for producing, such as steel and glass.

Examples including the 841-foot U.S. Steel Tower (1971), the glass and steel Four Gateway Center (1960), and the aluminum-faced tower at 201 Stanwix Street that once housed Bell Telephone (1958).

The city's second renaissance in the 1980s under Mayor Richard Caliguiri focused on diversifying business in the region. This period brought the construction of PPG Place (1984), One Oxford Centre (1983) and the light rail system.

Don't Edit

Downtown Pittsburgh as seen on April 18, 2017. (Barry Reeger | Special to PennLive)

Don't Edit

See more of Pennsylvania from the sky

Don't Edit

See more vintage Pennsylvania