An ambulance is a type of van that is used to take sick or injured people to a hospital or doctor's surgery. Ambulances often have emergency equipment in them so ambulance officers can save people's lives when they arrive instead of just driving them to the hospital. Ambulances are also used to take people from one hospital to another.
The word 'ambulance' is written backwards on the front of an ambulance so people in cars can read the writing in their rear view mirrors.
A blimp is very similar to a zeppelin, but a blimp does not have a supporting structure inside the big, bullet-shaped balloon that holds it up. Blimps have a compartment under them for people to ride in, and are moved forward by propellors.
A canoe is a small, narrow boat that moves forward as you paddle, like the people in the picture.