It's easy to look at this picture and wonder, "why is this umbrella so special that it is locked in a glass case?" But that's before you learn it was a brilliant Soviet spy weapon:
So it was that one day, while Markov was walking to his car in London, he felt a sharp bite on his thigh. When he turned around he saw nothing, only a man who fumbled briefly with an umbrella before running off. The next day he became deathly ill, and died, as one is wont to do when becoming deathly ill. To this day no one has ever been tried for the murder.
Yes, a man shot him with an umbrella that held a BB gun covered in deadly poison. Read about more insane spy weapons over at Cracked.
It wasn't a BB....a BB is 4.5mm or .177 caliber. Markov was shot with a ball bearing 1.52mm.
And the projectile wasn't covered in poison, it was covered in wax, after cavities had been drilled into the ball bearing and stuffed with ricin.
All of which were perfectly obvious if you actually take the time to read the article that you're linking to.