If you're a photo enthusiast and like to travel with a lot of gear, watch out for thieves who feel equally enthusiastic about it.
They generally operate as a group of up to five or six people who rush up to you and seem to want to show you something.
They hold a large card or document right under your nose, clamoring for your attention. While this is going on, one of them slips off the lens of your camera and then they all walk off in different directions.
Even if you spot that your lens is gone, your chance of finding the thief and then doing anything about it are strictly limited.
The whole thing is usually over in a matter of seconds.
You can see a video of exactly how it unfolds in St Petersburg, Russia, on a British newspaper site: https://www.express.co.uk/travel/articles/846187/viral-video-theft-trick
As you'll see, some deft handwork prevents the victim from getting his lens back.
Action: If you're accosted by this type of group, hold tight to your camera gear. If it's safe to do so, turn and walk away.
Better yet, it your camera make allows it, use a lens lock.