The nature of espionage, obviously, is that much of what goes on behind the scenes is shrouded in secrecy. This is largely true for the gadgets CIA developed throughout the organization’s history. Of the some 20,000 gadgets the clandestine agency has used, only about 600 have been declassified.

You can inspect some of those select, declassified few at the CIA Museum in Washington, D.C., where museum director Toni Hiley says even the more archaic tools serve as inspiration for tomorrow’s contraptions. “Revisiting technology is something we always do in the world of espionage,” Hiley told Tech Insider. “There’s no such thing as technology that’s too old for operations.”

Here are some of the most interesting gadgets from the declassified bunch.

1. An intruder detection device.

This may not be the sexiest-looking tool, but it certainly got the job done. Equipped with a built-in antenna, this Cold War-era device worked to detect enemies from as far as 1,000 feet away through sensing vibration, and transmitting the warning to the CIA through radio signals. Of course, its appearance was designed to camouflage with soil.

2. A radio disguised as a pipe.

These days, this would probably draw more attention than a radio itself. But in the 1960s, this men’s pipe concealed a radio receiver, which was configured to direct sound from the jaw bone to the ear canal.

3. A robot fish named Charlie.

This radio remote-controlled robot catfish was developed by the CIA in the 1990s to detect signals from enemy boats underwater. “Charlie” has his own microphone and propulsion system.

4. A miniature camera disguised as a cigarette pack.

In the 1960s, a 35-mm Tessina film camera was one of the smallest and quietest on the market, which made it perfect for concealing it in a pack of Parliaments.

5. A “bug”, disguised as a bug.

This fake dragonfly may be tiny, but it’s outfitted with the microphone the size of a bead (hidden in its head) and a mini engine. Called the “Insectothopter”, the CIA designed the bug in the 1970s. It can fly 650 feet for 60 seconds via remote control, with its wingspan allowing it to take flight without difficulty. But, alas, the spy agency’s insectothopter was no match for even light, 5-mph crosswinds. The CIA allegedly never deployed it.

6. A spike for dead drops.

This hollow stake was designed to hold film and documents in the 1960s. Operatives would fill the container with information and stick it in soil at a prearranged location for another agent to retrieve later.

7. A coded compact.

This makeup contraption holds a secret code, which is revealed when the mirror is tilted at precisely the right angle.

8. A carrier pigeon.

Operatives strapped lightweight cameras to carrier pigeons during WWII to collect hundreds of photos more detailed than they could hope from airplanes — the birds were able to get hundreds of feet lower to the target.

9. A hand-crank drill.

This toolkit was designed to aid with some important manual labor in the late 1950s: drilling holes in brick walls to conceal microphone surveillance.

10. A hollow ‘silver dollar.’

This tiny vessel was designed to hide messages or film that agents could pass to each other without attracting attention.

H/t TechInsider