It's the scent of terror.
Russian activists have created a perfume with notes of gunpowder, ash, stale paper and ink -- housed in a real Soviet bullet shell -- and presented on a bed of soil taken from near the site of mass graves.
It's a protest against plans to open a posh perfume shop in a building where thousands were sentenced to death during Stalin's Great Purge.
The building was a courthouse at the time, just 500 meters from the Kremlin.
The city's Gulag History Museum believes some 31,000 people were handed death sentences there in the 1930s, then executed elsewhere.
Nikita Petrusyov is the activist campaign's creative director.
(SOUNDBITE) (English) CREATIVE DIRECTOR OF , NIKITA PETRUSYOV, SAYING:
"A symbol of this awful, absolutely crazy situation. A luxury boutique inside the house of executions, where thousands of people were killed and which is associated with the darkest page of our history."
The smell of Perfume Number 23 is designed to evoke the terror of that time. The 23 is for the street address.
This was the response from someone smelling it for the first time.
(SOUNDBITE) (Russian) UNNAMED RESIDENT, SAYING:
"It smells like a basement. A heavy, unpleasant smell."
The building's owners, who want to develop the perfume boutique on the site, didn't respond to requests for comment
It's not clear just who'll wear the campaigners' somewhat spooky scent.
But they hope it'll make sure their protest creates a stink.