Three explosions shook St Petersburg's Vyborgsky district last Tuesday.
Rather than running in panic or diving for cover, residents from nearby apartment blocks came to their windows to watch scientists from a local research laboratory demonstrate a new explosive device to potential customers.
The explosions were hardly felt, yet the impression left by the display was lasting: a thick metal bar torn apart and a steel sheet (imitating a safe door) with an impressive new hole.
To demonstrate the potential life-saving properties of the new device, a hand grenade's fuse was blown from the grenade's body, leaving orange-colored TNT safely inside.
This explosive tool can be used to defuse terrorist devices, such as bombs, hand grenades or mines, by igniting a small explosion that destroys the device's firing mechanism.
It does so by concentrating the energy of the small explosion inward in a way that does not activate the original explosives.
The invention is simple, consisting of a piece of wire, which can easily be positioned in a loop around the device to be defused.
The wire is attached to a lead running to a control box.
The operators then detonate the fuse of the bomb by running a current through the wire. This sets off the explosion and concentrates its force at the same time.
The device was originally designed for the space program to precisely disconnect different objects in space.
"But as space programs are less popular now than terrorism issues, we prepared our devices to defuse explosives and rescue people on the earth instead," said Yuri Berezuyev, one of the device's creators.
Mr Berezuyev, who works at the Technological University's SKTB technology construction bureau, said the city police department, a fire brigade and 23 tax police brigades in Russia have already started using the device.
With the device, a fire brigade can quickly remove metal doors and bars to save people from their well-protected homes in the event of a fire.
Alternatively, the tax police can quickly get undamaged documents from safety boxes, and the police can use it for emergency-rescue task forces.
"A minimum of explosives is used," said Mr Berezuyev.
"They are so cheap that even our impoverished police can afford to buy them," he said.
Visiting foreign experts were very surprised by the idea of using explosives to cope with explosives, he added.
"But this is very Russian," Mr Berezuyev said, referring to a common Russian idiom to remove a wedge with another wedge.