The BSB exists because eleven Israeli athletes died in Munich in 1972. The massacre at the Olympic Village convinced every European government that ordinary police could not handle a hostage standoff with trained terrorists, and one after another the continent's countries built specialized units to close the gap. The Netherlands raised several of these new Bijzondere Bijstandseenheden - Special Support Units - drawing on marines, regular police, and Marechaussee snipers. But Marechaussee command noticed a problem hiding in the new architecture. The elite units could only be activated during an active terrorist threat. The day-to-day work of guarding ministers, escorting gold, watching organized crime - that fell into a gap nothing was designed to fill. In 1975 the BSB was created to fill it. The very first class of operators trained under West Germany's GSG 9, the unit forged by the same massacre, and in 1976 the BSB went operational with just twenty-four men.

The brigade's home sits on what used to be a piece of the Cold War. Soesterberg Air Base, just east of Utrecht near the hamlet of Huis ter Heide, hosted United States Air Force fighters for decades under the cover name Camp New Amsterdam. American F-15s once scrambled from this runway. When the base closed and the Americans went home, the woods stayed and the buildings stayed, and in 2015 the BSB took possession of a new headquarters on the grounds. Photographs from that year show operators abseiling down the side of the new building - a publicity image with a quiet message about what happens inside. The fields around the base are now part of a nature area, but the perimeter where the brigade trains is not on any tourist map.

The BSB lives behind three doors. The Security Division supplies the close-protection details that follow Dutch and foreign military officials through high-risk capitals. Where the National Police's diplomatic-security service trains for routine threat environments, the BSB specializes in places where the risk has already arrived - the Dutch ambassador in Baghdad, the embassy in Kabul, the visiting general in a country the Foreign Ministry calls unstable. Behind the second door is the Observation Team. Operators trail people for weeks, sometimes longer, building what the trade calls a pattern of life. Unlike their intelligence-service counterparts in the AIVD, BSB observers are always armed. The third door opens onto the Arrest Team, established in 1994, the people the Marechaussee sends when the suspect is military, or armed, or both.

Two assignments capture the strange shape of the BSB's work. When the Dutch central bank moves gold - heavy pallets of bullion through the streets of Amsterdam - BSB operators in tactical gear travel with the convoy. Photographs from a 2020 transfer show them standing on a quiet plaza, weapons ready, while a forklift handles a ton of metal worth more than most lives. The other assignment is more politically charged. In March 2017 the brigade quietly took over the personal protection of Geert Wilders, the divisive Dutch politician who has lived under permanent threat for nearly two decades, after two officers from the National Police's protection service were accused of leaking sensitive information about his security arrangements. The Marechaussee, being a military body, runs to different rules. A leak from inside the BSB has not been reported.

The BSB was designed as a bridge - that was the word the Marechaussee used in 1975, and it still fits. On one side stand regular police, equipped to keep order in the daylight. On the other stand the Marines' M-Squadron and the rest of the country's special-operations apparatus, kept in reserve for the worst nights. The BSB lives in the middle, doing the work no one else is trained for and almost no one knows about. From cruising altitude over Utrecht, the headquarters near Huis ter Heide is just a cluster of low buildings among the trees of the old air base. From inside the perimeter, it is the operational heart of a 24-hour Dutch security system most Dutch people will never see.