A building under renovation in Den Bosch collapsed late Saturday night, leaving a gaping hole in the city's main square. The collapse happened after 11 p.m., and rescue workers were still uncertain if anyone was buried in the rubble as midnight approached. Cafe patrons sitting nearby said the incident was surreal. It was just "as a house of cards would collapse," one person told the Volkskrant. Others said it seemed like the building crumbled in slow motion. A trauma helicopter was immediately dispatched to the scene, along with at least six fire trucks, two ambulances and multiple police at the location, freelance journalist NoÃ«l van Hooft wrote on Twitter. At the time of the collapse, workers were testing large, special lighting for a show on artist Hieronymus Bosch. The lights were be used to make the rubble more visible for rescue workers in the aftermath. It happened at a corner building located on the Markt at Hinthamerstraat. Demolition work on the ground floor Pearle optician's location began just after the store closed, and continued until about 10 p.m., residents told broadcaster NOS. There were several units above the store that were used as apartments up until the last few weeks, according to the Telegraaf. The apartments were already being converted to warehouse space, and were no longer lived in, one area resident told the paper. A message on the Pearle website says the facility is closed due to the construction work due to take place there from Monday, February 29 through Friday, March 4. The shop normally closes on Saturdays at 5 p.m. and is closed on Sundays. The Pearle was located next to Bosch's birthplace, Van Hooft said. That building, known as "De Kleine Winst", or The Little Winnings, was left unscathed, according to multiple reports from the scene. A spokesman for the regional safety office does not believe there are any injuries, but is offering no guarantees, Omroep Brabant reported. Specially-trained dogs are at the location to help search efforts.