1797: Lucas Sullivant surveys what is now Franklinton, setting the stage for Columbus as a permanent settlement.

1797: Lucas Sullivant surveys what is now Franklinton, setting the stage for Columbus as a permanent settlement.

1893: Part of the City Beautiful movement, a Victorian-style greenhouse is built on former fairgrounds known as Franklin Park.

1897–1899: A third version of Union Station (with stores and offices) increases access to Columbus via railroads.

1899: Additions of a roller coaster and gardens from the World's Fair turn Olentangy Park into a destination.

1922: Ohio State University opens Ohio Stadium, holding 66,210 fans and built with materials from Marble Cliff Quarry.

1929: Port Columbus International Airport opens as an integral part of the first air-rail (air-by-day, rail-by-night) transcontinental passenger line.

1929: Battelle Memorial Institute, founded by industrialist Gordon Battelle, opens, focusing on research in metals and material science.

1964: With support from business leaders, COSI opens in the overhauled Memorial Hall on East Broad Street.

1979: Centrum, Capitol South's ice- and roller-skating rink, opens in an effort to keep people Downtown.

1976–1977: Union Station is demolished to make way for what is now the Greater Columbus Convention Center.

1981: The city unveils Red, White & Boom, attracting 30,000 people to Bicentennial Park.

1982: Roy Lichtenstein creates "Brushstrokes in Flight," for Port Columbus International Airport.

1988: Artist James T. Mason begins creating the characters of George Seurat's "A Sunday Afternoon on the Isle of La Grande Jatte" for what would become Topiary Park.

1989: The fully enclosed City Center Mall replaces Centrum at Capitol South but closes in 2002 due to competition from suburban malls.

1989: Former Central High School is transformed for Son of Heaven: Imperial Arts of China, a traveling exhibition of 225 Chinese treasures. The show loses money and receives public funding to break even.

1992: AmeriFlora, the first international floral and garden exhibition in the U.S., is a 26-week exhibition that operates at a loss in Columbus.

1999: Crew Stadium, the first soccer-specific stadium in the U.S., opens north of the Ohio State campus.

1999: COSI relocates to a new facility, designed by Japanese architect Arata Isozaki and incorporating the former Central High School, along the Scioto River.

2000: Nationwide Arena opens and is later sold to the Franklin County Convention Facilities Authority.

2002: In homage to Columbus' 1888 arches (hence the Arch City nickname), 17 LED-lit arches illuminate the Short North.

2004: The Buffalo Destroyers relocate to Columbus before the American Football league folds.

2004: The I-670 Cap connects the Short North to Downtown with restaurants and retail above the highway.

2007: Federally funded streetcars appear in MORPC's plan as a priority for 2011 but don't make it to fruition.

2009: Penn National proposes Hollywood Casino be built Downtown. In 2012, it opens in west Columbus.

2010–2011: A green space to replace City Center, Columbus Commons hosts 300,000 visitors in its first year.

2011–2012: Two new bridges encase the Scioto Mile, a collection of fountains, benches and walkways along the Scioto River.

2012: A citywide Bicentennial celebration leads to initiatives to try to attract the Women's Final Four NCAA tournament and the Democratic National Convention to Columbus.

2014–2015: A dam removal in the Scioto River is designed to improve water quality and drive economic development Downtown, with a focus on Franklinton.