This video from London, England is called Shark Week: Finsbury Shark.
From Wildlife Extra:
Great white shark spotted in north London boating lake
Joggers, dog-walkers and early morning commuters in Finsbury Park in North London this week were treated to the unexpected sight of what appeared to be a great white shark fin slicing through the water among a group of rowers on the boating lake.
Campbell used a hand-carved polystyrene fin mounted onto a 3m tubular frame, with internal ballast and flotation devices to guide the shark. An underwater pulley system, connected between two points on the shoreline by an underwater steel cable, allowed the shark fin to travel at pace across the water.
Cameras were set up around the lake to capture the reactions of the unsuspecting boating enthusiasts. One person in every boat was aware of the prank.
A spokesman for Discovery Channel commented: “When you go for a genteel early morning row around the shallow Finsbury Park Boating Lake, the last thing you would expect to encounter is one of nature’s most renowned predators. All of the boaters saw the funny side and we can assure everyone that it is perfectly safe to go back in the water!”
Discovery Channel’s Shark Week, which also features on Animal Planet, begins on Sunday 10 August and features documentaries such as Airjaws Finding Colossus, in which shark experts Chris Fallows and Jeff Kurr visit legendary Seal island in South Africa in search of great whites and Mythbuster Jawsome, which counts down the 25th biggest shark myths of all time.