Omni William Penn Hotel

Steel Plaza is a station on the Pittsburgh Regional Transit's light rail network, located in Pittsburgh, Pennsylvania. It serves the city's Downtown district and is located at the intersection of Grant Street and Oliver Avenue. The station consists of an outbound (southbound) side platform and an inbound island platform, with one track for trains to Wood Street and the other for a disused branch line to Union Station. The station has rights to 4.25 acres underground Mellon Green and is accessible by means of a tunnel that connects BNY Mellon Center and the US Steel Tower. The busiest station in the system, it provides access to eastern and central portions of downtown, including the city's tallest buildings, the US Steel Tower and BNY Mellon Center. Major office buildings including the Gulf Tower, 525 William Penn Place, and the Koppers Building are also only a block away, along with the many early 20th-century skyscrapers that make up downtown's inner core. The city's Uptown (commonly known as The Bluff) neighborhood, which includes PPG Paints Arena and Duquesne University is also within a short walk.

The Pittsburgh & Steubenville Extension Railroad Tunnel, also known as the Panhandle Tunnel, was originally built for the Pittsburgh and Steubenville Extension Railroad in Pittsburgh. It officially opened for rail traffic in 1865.

The Union Trust Building is a high-rise building located in the Downtown district of Pittsburgh, Pennsylvania, at 501 Grant Street. It was erected in 1915–16 by the industrialist Henry Clay Frick. The Flemish-Gothic structure's original purpose was to serve as a shopping arcade.

The James Reed Building or the Reed Smith Building is a historic building in Pittsburgh. It was constructed in 1902. It is in the Beaux-Arts architecture style. For many years, the primary tenant had been Reed Smith law firm. The buildings namesake is one of Reed Smiths founders, James Hay Reed. Reed Smith bought the nine-story building in 1984 for $5.82 million as 435 Sixth Ave Associates. In 2007 Reed Smith decided to relocate its corporate headquarters to Three PNC Plaza and sell the building, which had a market value of $16.78 million. The downtown Pittsburgh office vacancy rate at the time was 20%, driving down the value of the building. In October 2008, the building was purchased by Mika Realty Group of Los Angeles for $6.5 million. Mika Realty, owned by Michael Kamen and Gerson Fox, purchased the building under the name 600 William Penn Partners LLC. Kamen and Fox also purchased the nearby Union Trust Building 6 months prior.In 2009, Reed Smith law firm moved its corporate headquarters to Three PNC Plaza. Mika Realty was never able to find a tenant to replace Reed Smith, the building remained vacant, which led to bankruptcy in 2011. PMC Property Group purchased the building in September 2012 for $5.5 million in a U.S. Bankruptcy Court auction in Los Angeles.The building was redeveloped into a 249-room Hotel Monaco, opened in January 2015.

The Alcoa Building (a.k.a. the Regional Enterprise Tower) is a 410-foot-tall (120 m) skyscraper in Downtown Pittsburgh, Pennsylvania. It was completed in 1953 and has 31 floors. It is the 15th tallest building in the city and is adjacent to Mellon Square. A unique radiant heating and cooling system is contained in the ceiling: since there are no pipes, radiators, or air conditioning units along the exterior walls, an additional 15,000 square feet (1,400 m2) of rentable space was gained. Also, the windows rotate 360 degrees so they can be washed from the inside.Originally the headquarters for the Aluminum Company of America (ALCOA), the unique aluminum walls of the building are 1/8 inch thick, which gives the building a very light weight and economical design. It was the first skyscraper with an all-aluminum facade. Upon ALCOA's 2001 relocation to a new headquarters building on Pittsburgh's North Shore near PNC Park, the old ALCOA Building became a home to government entities, regional nonprofits and small start-up companies including the RIDC.

Mellon Square is an urban park in Downtown Pittsburgh, Pennsylvania. It is the first Modernist park built above a parking garage. With its distinctive black, white and green geometric pavement, it is a prominent urban oasis and gathering spot in Downtown Pittsburgh. The square, bounded by Smithfield Street, William Penn Place, and Oliver and Sixth Avenues, is surrounded by prominent downtown buildings including the Oliver Building, 525 William Penn Place, Omni William Penn Hotel, and the Regional Enterprise Tower. It has long been a popular lunchtime destination for downtown workers. In addition, retail shops are housed underneath it, along the Smithfield Street side of the square.

The Pittsburgh Central Downtown Historic District is a historic district in the Central Business District of Pittsburgh, Pennsylvania, United States. Bounded by Wood Street, Forbes Avenue, Grant Street, and Liberty Avenue, it was listed on the National Register of Historic Places on December 17, 1985. Its boundaries were expanded on May 2, 2013.The original district includes 26 buildings, 20 of which are considered contributing including a few small former residences built in the mid-19th century. The Frick Building and U.S. Post Office and Courthouse are contributing properties and are also listed separately on the National Register of Historic Places. Other notable contributing properties are the Gulf Tower, the William Penn Hotel, the Oliver Building, Mellon Square, the August Wilson Center, the Federal Reserve Bank Branch, Gulf Tower, the Frank & Seder Building, the Koppers Building and Trinity Cathedral.

BNY Mellon Center is a 55-story skyscraper located at 500 Grant Street in downtown Pittsburgh, Pennsylvania. Standing 725 ft (221 m) tall, it is the second-tallest building in the city. Announced on March 27, 1980, the tower was completed in June 1984. It was initially planned to be the world headquarters of the Dravo Corporation (now Carmeuse Corporation) by its majority owner at the time and current neighbor U.S. Steel until Dravo was purchased in 1983. Upon opening, the building was named One Mellon Center after Mellon Financial Corporation, which used the tower as the company's global headquarters. In 2007, the company merged with Bank of New York to form The Bank of New York Mellon; the resulting corporation continues to use the building as one of its major offices. In 2008, the building was renamed to its current moniker as part of a branding initiative by The Bank of New York Mellon.Prominent features of the building include its eight-sided design and mansard roof. The tower is connected to the U.S. Steel Tower through a tunnel which passes through Steel Plaza subway station. BNY Mellon Center is the ninth-tallest building in Pennsylvania (as well as the second-tallest within the state outside of Philadelphia) and 195th-tallest skyscraper in the world, and also the building with the highest taxable property value in Allegheny County, surpassing even the U.S. Steel Tower. On clear days, it is possible to spot the building from as far as 50 miles away, usually from the top of Chestnut Ridge.

The Allegheny HYP Club (Harvard-Yale-Princeton Club) is a private social club in downtown Pittsburgh, Pennsylvania. Located at 617-619 William Penn Place, it was built in 1894 and was added to the List of Pittsburgh History and Landmarks Foundation Historic Landmarks in 2002. On July 1, 1997, the club absorbed the Pittsburgh Club membership and assets.The Pittsburgh Harvard-Yale-Princeton Club was formally founded on November 7, 1930. The club merged with the Three Rivers Stadium based Allegheny Club in 2002 after Allegheny had filed for bankruptcy protection.

525 William Penn Place (also known as the Citizens Bank Tower) is a skyscraper located in downtown Pittsburgh, Pennsylvania. It was completed in 1951 for the Mellon National Bank and the U.S. Steel Corporation. At 520 feet (160 m) tall, it was the second-tallest building in Pittsburgh until 1970, and the third-tallest until 1984. The building has 41 floors and approximately 950,000 square feet (88,000 m2) of office space. Presently it is the third-largest office building by square feet in downtown Pittsburgh. In 2016, BNY Mellon sold the building for $67.65 million.

The Carnegie Building, also known as the Carnegie Steel Building, was a high-rise building in Pittsburgh, Pennsylvania.

Carnegie Learning, Inc. is a provider of K-12 education solutions and services for math, literacy and ELA, world languages, and applied sciences. Carnegie Learning, Inc. is located in the Union Trust Building in Pittsburgh, PA.