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Forgotten plans for a 12-story sphere inspired by the U.S. Geological Survey’s (USGS) Earth Resources Observation and Science (EROS) Center are part of an exhibit at the Old Courthouse Museum in Sioux Falls, South Dakota.

1966-1979: How Sioux Falls Ingenuity Secured the Center

1966-1979: How Sioux Falls Ingenuity Secured the Center

1980-1999: Through Uncertainty to a Firm Footing

1980-1999: Through Uncertainty to a Firm Footing

2000-2023: Data and Science Surge

2000-2023: Data and Science Surge


A museum display of a science center
Part of the display of the Unisphere project at the Old Courthouse Museum in Sioux Falls, South Dakota. The concept of the project, originally called “Erosphere,” included a science center, farm of the future, visitor center, and space for scientific conventions. The Unisphere display is part of an exhibit featuring Sioux Falls projects that never came to fruition.

“Designing Sioux Falls” features the Unisphere display of an Epcot Center-like model of a futuristic science center, the result of one man’s fascination with our Earth-observation mission.

Louis C. Warren was the Sioux Falls Chamber of Commerce president in 1970—and an enthusiastic advocate of bringing EROS to the city. Once Sioux Falls secured the bid, he began to seek ways to build on the groundswell of technical innovation he was sure would follow.

“I cry to think I am 60 years old,” he told The Rotarian magazine for a February 1972 article. “One pass of ERTS-A (Landsat 1) will spew out facts like rain!” That same month, he registered a nonprofit business with the state of South Dakota called Earth Resources Observatory, Inc.

By April 1972, Warren unveiled a model of what was then called the Erosphere project to a crowd of 400 businessmen at the Holiday Inn, touting its ability to transform Sioux Falls into a “city of dreams.” He envisioned a 230-foot diameter, 12-story sphere that would attract up to 2 million people during the tourist season, rivaling and even outpacing visitors to Mount Rushmore!

The whole project was inspired by EROS. An April 24 story in the Argus Leader, the local newspaper, about the event described the Erosphere as a learning center to complement the activities of the EROS center, which had just broken ground on April 14 and had not yet even processed one scene from Landsat 1, which wouldn’t even launch until July.


Pecora I EROSPHERE- 1975
The model of the Erosphere displayed at the first William T. Pecora Memorial Remote Sensing Symposium in 1975.
Poster for a science center project
A marketing poster of the Unisphere project on display at the Old Courthouse Museum.
Model for a science center project
A side view of the Unisphere display at the museum.

Expanding the Vision

Posters for a museum display
Interpretive description of the Unisphere project. Note the picture of Louis C. Warren on the bottom left.

Warren planned on a grand scale. Visitors in groups of up to 175 would take an elevator to the observation deck at the top of the dome, where a planetarium would take them “on a simulated journey with the ERTS satellite as it monitors resources of the earth.” They would then descend through 36 “animated diorama” exhibits, 12 of which were to be rotating exhibits featuring the “1,000 topics of study” Warren estimated to be researched at EROS.

The story even reported that EROS project director William Fischer contacted Warren, signaling his encouragement for the “living science center.” Later, the Erosphere model was displayed at the first annual William T. Pecora Memorial Remote Sensing Symposium in October 1975, also held in the Sioux Falls Holiday Inn.

Warren’s dream gained momentum. The South Dakota Legislature gave Warren \$130,000 under the Bicentennial project to create a model developed by Spitznagel Partners Inc.—the same architectural firm that designed EROS. The nonprofit then commissioned an economic feasibility assessment from a Massachusetts firm, the Arthur D. Little Company. The company’s report suggested the sphere complex would garner \$5.5 million in tax revenue to Sioux Falls and $7.1 million for South Dakota, with 500,000 visitors in the first year.

Most significantly, a location was designated: the then-undeveloped land southeast of the intersection of Interstates 90 and 29. The 245-acre campus now was expected to host an “exhibit space, an eartharium, a Farm of the Future, an Earth Studies Institute, theatres, restaurants, motel rooms and convention space, parking, campgrounds, visitor information and open space for public recreation and community events.” A March 1980 op-ed by Warren in the Argus Leader mentions that EROS could “establish public information facilities and conduct workshops” in the sphere.

A Fading Dream

Hours for a museum
Hours displayed for purpose of visitors to the Unisphere exhibit at the Old Courthouse Museum in Sioux Falls, South Dakota.

To avoid over-identification between the Erosphere and EROS, however, the project’s name was changed to “Unisphere, Forum of the Future.” And maybe that’s ultimately a good thing. For whatever reason, despite acquiring city, state and federal subsidies and the rights to buy the land, the project never attracted the national investments needed to begin construction. An October 3, 1982, Argus Leader feature questioned the timing of the Unisphere, noting that Disney’s similar Epcot Center had opened only two weeks previously and that the June 15, 1983, deadline for fundraising to buy the land was fast approaching. 

Today, all that remains of Louis C. Warren’s grand scheme is the Spitznagel model of the project and some brochures and posters, all on display at the Old Courthouse Museum until spring. The original model that Warren displayed in 1972 to businessmen and then later at the Pecora Symposium was rumored to be on display at a local bank for a while, but its whereabouts are currently unknown.

Closeup of a museum display
A close-up view of the Unisphere model.

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