During "Cannon fest" at the Alamo, guns are unlimbered and set up at various spots on Alamo Plaza. The encroachment of the city on the old mission means that there is densely populated buildings in any and every direction. Demonstrations are provided on how to load, shoot, and service the guns, and little tykes are encouraged to use worms, sponges, and rammers while the vent is covered by the appropriate finger stand (no thumb... if the thumb goes, one has lost the use of the hand... ring finger and pinkie instead) to prevent air getting into the breech and to create an air tight seal and "vacuum" with a satisfying "pop" when the sponge is withrdrawn...
Not every place has the luxury of a completely clear "down range" area for the piece. An entertaining photo, certainly.