Cosman Citroen arrived in Surabaya from the Netherlands in 1915. Within a year, he had secured the commission for the city's new municipal hall -- a remarkable achievement for a newcomer, suggesting either exceptional talent or exceptional connections in the colonial establishment, likely both. His first proposal in 1916 placed the building at the Stadstuin, near what is now Pasar Besar in front of the Heroes Monument. By 1920, the municipality had purchased land in Ketabang, a new district east of the Kali Mas river, chosen precisely because its emptiness allowed for grand plans. Citroen's revised 1925 design called for four building masses arranged around a central courtyard. It was the kind of ambitious colonial vision that rarely survived contact with colonial budgets.

The economic troubles that began in 1921 and deepened through the decade shrank Citroen's four-wing plan down to one. Only the rear north-side building was ever completed; the unfinished wings became the park that now fronts the structure. Construction dragged on for years, and funding came piecemeal from unlikely sources. The General Dutch East Indies Electricity Company, ANIEM, donated the boardroom furniture. Sam Liem Kongsi provided the boards in the mayor's office. J.J. Zeidel contributed a marble plaque for the hallway. W.J. Stokvis gave an antique silver lamp and a painting. Lindeteves-Stokvis donated a refrigerator. Even the Dutch Gas Company chipped in. When the town hall finally opened in November 1927, it was as much a community effort as a government project -- assembled from the generosity of private citizens and corporations who each left their mark on the building's interior.

The completed building stretches 102 meters long and just 19 meters wide, a proportionally narrow structure that maximizes exposure to prevailing breezes. Its facade reads like Cubism transplanted to the equator: sharp geometric volumes cast deep, contrasting shadows in the high tropical sun. But the aesthetic is inseparable from the engineering. The double-layered roof -- a signature of the New Indies Style -- creates a ventilation gap that draws hot air upward and out, a passive cooling system centuries before air conditioning became standard. Surrounding galleries serve double duty, protecting interior walls from direct sunlight and shielding them from the torrential rains that arrive predictably every afternoon during the wet season. The building is primarily reinforced concrete with a steel roof frame, modern materials deployed for a distinctly local purpose.

Inside, the influences multiply. The interior design draws from the Amsterdam School and De Stijl, two Dutch movements that were reshaping European design in the same decades Citroen was building in Surabaya. The ground floor houses the central administration, constituency chamber, and population registration department. Upstairs, the boardroom sits in the center, flanked by the secretary's office, waiting rooms, and the municipal archives. Citroen designed the furniture as well as the building, giving the interior a coherent aesthetic vision that runs from the architecture down to the chairs. His other major work, the headquarters of the Dutch East Indies Railway Company in Semarang -- now the celebrated Lawang Sewu -- shares a similar ambition to bring European modernist principles into conversation with tropical reality. Both buildings survive as working monuments to a brief moment when colonial architecture stopped pretending Java was Holland and started designing for where it actually was.