Amsterdam’s entire metro network ground to a halt around noon on Sunday.
The cause was a failure in the GVB traffic control system, the equipment that watches and directs every train on the network.
With that system down, no metro could safely move anywhere in the city.
Trains emptied at the platforms
Trains that were between stops were driven on to the next station.
There, all passengers were asked to leave, and platforms filled with stranded travellers.
GVB staff pointed people toward trams and buses, which kept running normally throughout.
The operator said its teams were working hard on the fault while passengers were informed at the stations.
Running again after an hour
Around 13:20 the system came back and metros began rolling again.
GVB warned that delays would linger through the afternoon as trains returned to their normal rhythm.
By Monday morning the network is expected to run its regular timetable.
The disruption was a reminder of how much of the city leans on four metro lines, especially on a summer Sunday full of visitors.
If the metro is disrupted, check our guide to Amsterdam buses and trams for another way around.