In 1940, the city commissioned Carl Milles to design a fountain, The Meeting of the Waters, on Aloe Plaza in front of Union Station.

In 1994, his administration cleared the two blocks between 8th and 10th streets for the mall, in the process removing the landmark Western Union Building.

Next to the Library, City Hall, and the Civil Courts Building, a civic room to hold public events was recommended.

Following this, a conservancy group was formed to maintain the mall, help raise money for this purpose, and carry out the rest of the objectives of the master plan.

The Luther Ely Smith Square is controlled by the National Park Service, and is located directly between the Arch Grounds and the Old Courthouse.

As winners of the 2009 international Framing a Modern Masterpiece design contest, Michael Van Valkenburgh Associates re-imagined Luther Ely Smith Square extending to form a park over Interstate 70, physically connecting the Arch grounds to the city of St. Louis for the first time.

Land for the courthouse was donated in 1816 by Judge John Baptiste Charles Lucas and St. Louis founder Auguste Chouteau.

[4] Beginning in 1861, William Rumbold replaced the cupola with an Italian Renaissance cast iron dome modeled on St. Peter's Basilica in Vatican City.

Due to its ownership by the National Park Service, the 2009 mall master plan didn't identify any improvements for the Old Courthouse aside from extending the "Hallway" through the block.

[12][13][14] After city voters passed a $2 million bond issue in 1962, the eastern half opened in 1965 between Broadway and 6th Street.

[12] In 1986, 6th Street was closed and Kiener Plaza was extended west with the Morton D. May Amphitheater, designed as a postmodern Roman ruin with a capacity for about 500 people.

[16] It reopened on May 19, 2017, and saw the sunken amphitheater replaced with street level open spaces, a playground, a water feature, and a lawn that can accommodate up to 3,000 people.

This plan proposed formal park blocks with central lawns and tree plantings between 12th Street and the Arch Grounds.

[12] In 1977, developer Donn Lipton submitted a plan for this block that would have kept most of the historic buildings in place while turning the alley into park space.

[13] Despite the Landmarks Association of St. Louis moving into the Title Guaranty building in an effort to save it, all three were demolished by the end of 1984.

[17][18] The 2009 master plan only suggested bringing the building's outdoor plaza down to sidewalk level on Market Street and continuing the "Hallway" along the Mall.

[12] 1960's A Plan for Downtown St. Louis suggested creating formal park blocks east of 12th Street to the Arch Grounds with central lawns and uniform tree plantings.

[12] In 1977, developer Donn Lipton submitted a plan for the blocks between 7th and 10th streets that would have kept most of the historic buildings in place while turning the alleys into park space.

[13] The 2009 master plan identified the two blocks between 8th and 10th streets as the "Citygarden," an urban sculpture park with seating, plantings, temporary art installations and a restaurant called the Terrace View.

[22][23] Some of the artists represented include: Donald Baechler, Niki de Saint Phalle, Jim Dine, Mark Di Suvero, Jean-Michel Folon, Laura Ford, Aristide Maillol, Ju Ming, Igor Mitoraj, Julian Opie, Tom Otterness, Mimmo Paladino, Martin Puryear, Bernar Venet, and Jack Youngerman.

A small expansion of the park opened in May 2024 and fully closed 9th Street, extended the serpentine wall and added three new pieces of artwork.

[32] The roof is made of cast aluminum and is topped by two 12-foot (3.7 m) high sphinx-like sculptures with the fleur-de-lis of St. Louis adorned on their chests.

[33] The building is frequently featured in the center of photos of the Gateway Arch from the Illinois side, as its location on the Mall is lined up in the middle directly behind the Old Courthouse.

The 2009 master plan didn't propose any specific improvements to the Civil Courts block, other than continuing the "Hallway" feature to the Civic Room.

These blocks were lightly landscaped and the only notable feature were formations of concrete and stained glass screens located around small fountains.

The Civic Room includes the original 1932 section and is planned to become the predominant space for outdoor festivals and events.

[40] The Neighborhood Room will include the 1960 addition and is to be primarily residential in nature, with facilities like lawns, playgrounds, sand-volleyball courts, and youth soccer fields for nearby residents.

[41]In 1923 city voters passed an $87 million bond issue that would fund public improvements, including a civic center downtown.

[42] Using funds from the bond issue the city cleared the block in front of Union Station and opened Aloe Plaza in 1932.

In 2024, the city is expected to break ground on the 20th Street Mobility Project which will see a shared use path constructed along 20th between the Mall and St. Louis Avenue.