First things first: Happy Birthday, Louis Kahn! Considered one of the most influential architects of his time, the Philly starchitect would have been 115 years young today. We began the birthday celebrations earlier this week by rounding up 10 residential homes designed by Kahn in the area.

But while those were actually built, the following projects never came to fruition. This is by no means a complete list, but one thing's for sure: If Kahn had had it his way, Philadelphia would have looked mighty different today.

City Tower Project—Leave it to Louis to reimagine the city's most iconic building, City Hall, and turn it into this trippy tower. This project began in 1952, and Kahn wanted it built—badly. In the paper "Critiques of Liberal Individualism: Louis Kahn's Civic Projects," author Sarah Williams Ksiazek notes that Kahn wrote to Ann Tyng, who played a major role in its design, "I cannot allow the grass to grow under my feet. [...] How long must I wait? [...] If a building must go there, who could do it better?"

Mikveh Israel Synagogue—When this synagogue planned a move into Center City, Kahn purportedly whipped up 10 designs for his friend Dr. Bernard J. Alpers, the vice president. Due to construction and maintenance costs, however, plans for the synagogue fell through.

Fleisher House—Proposed in 1959 in Elkins Park, this house is made of eleven square spaces, and five additional squares that function as covered gardens. It's said that this home was one of the most obvious examples of Kahn's rejection of functionalist opening forms.

Philadelphia City Planning: Market Street East—Market East may be coming into its own today, but beginning in 1960 Kahn envisioned a geometric neighborhood with towers that would have soared over City Hall. This particular project caused landscape architect Edmund Bacon, Kevin Bacon's father, and Kahn to butt heads. Bacon was quoted as saying, "Lou would say, 'wouldn't it be nice to put a curval stair way here, or wouldn't it be nice to put a little tower here.' Suddenly I realized that the purity of my communication was being encrusted by Lou's fantasies...It's an absolutely pure ignorance on Lou's part that you have no responsibility to prepare a system of a large order and you only do a little thing that comes along."

Philadelphia College of Art—Planned as an extension to Center City's Philadelphia College of Art, this addition would have been a mix of studios, workshops, offices, and a performance hall. The model shows that Kahn's building all-but ignored the heights of the surrounding buildings at the time.

Philadelphia City Planning: Triangle Area Redevelopment—In 1946 the City Planning Commission asked Kahn to redesign a 200-acre parcel bordered by the Ben Franklin Parkway, the Schuylkill River, and Market Street. The initial concept looked to design a sunken pedestrian esplanade similar to NYC's Rockefeller Center, according to Ed Bacon: Planning, Politics, and the Building of Modern Philadelphia. But by 1950, Bacon and Kahn parted ways on the project.

· Louis Kahn Architectural Archives [PennDesign]

· Map: 10 Homes Louis Kahn Designed in Philly [Curbed Philly]

· Louis Kahn Coverage [Curbed Philly]