Abdul-Baha, son of the Bahai Faith's founder Baha'u'llah, traveled to the Chicago area in 1912 and personally laid the cornerstone for what would become the Bahai House of Worship in Wilmette, on land Bahai contributors had purchased along Lake Michigan five years earlier. The building he set in motion took another four decades to finish. The French Canadian architect Louis Bourgeois developed the temple's distinctive nine sided design, refined after Abdul-Baha reviewed it during a 1920 visit to Haifa, and construction proper began in 1921, with the Foundation Hall usable as a meeting space by 1922, but the Great Depression and the Second World War repeatedly stalled the work, and the temple was not completed until 1953. Nine sides and nine entrances reflect Bahai numerological symbolism, nine being the highest single digit and, in Bahai teaching, a symbol of unity and completeness, so the building's geometry carries the same doctrine its dedication ceremony proclaimed.
It remains the only Bahai House of Worship in North America and one of only a handful in the world. Chicago's own religious geography grew far more through immigration than through any single monument, a large Catholic archdiocese built on Polish, Irish and Italian parishes and a major Jewish population, and Catholic identification leads the state today at twenty three percent of adults, per Pew's 2023-24 study.