There is a common and rarely lauded physics phenomenon which operates in cities with large transient populations of tourists; it is called tourist drift.
Newton describes momentum as the tendency for a body to remain in its current state of motion unless acted on my an outside force. On city streets the outside force is generally the edge of the sidewalk or pavement on the one side and the buildings on the other. Tourists wander at a 20 degree angle to these two boundaries following a zig-zag trajectory. No one knows why.
Tourist drift can be observed on any given day, on any walkway in any city in the world.
What makes tourist drift so unique, is that the rate of drift is both inversely and directly proportional to the desire of the city resident perambulator to reach her destination.
For example, if the city resident is in moderate haste, tourist drift operates so that the frequency with which the tourist changes trajectory across the walkway increases making it impossible to pass on either side.
However, should the city resident be in EXTREME haste, tourist drift causes the tourist to lose momentum completely and stop in the middle of the walkway to examine a map. This particular feature of tourist drift correlates directly with the number of pieces of oversize luggage the tourist is dragging behind them.
No one is sure what happens to tourist drift if the resident is not in haste because most city residents do not venture out of doors in tourist drift areas in their leisure time. This is why residents have often lived in a city their entire lives and never been to or seen the “sights”.
Enjoy the holiday weekend!