h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Cambridge is a very fine place to spot tourists. They come in many shapes and sizes, and can be divided into braod classes

Americanus Maximus - the common american tourist.
Features - Shorts, knee length white socks and sandles. The males commonly sport baseball caps.
Habits - Inability to see what is in front of them. For example, they will often
ask the natives questions such as (when standing on the bridge) "where is the river?"

Voyerous Japonica

Features - Always carries large amounts of photographic and surveylance equipment.
Habits - All areas are suitable for photographing, including shots looking through students windows, and especially pictures with many of their friends and relatives standing on the lawn behind the sign saying "Please keep off the grass"


Le serpent Francais

Features - Can appear, at first glance, to be merely a large group of French schoolchildren, however, on closer inspection, they prove to be inseperable and joined by some bio-symbotic link.

Habits - Le serpent Francais is never happier when motionless. Favourite haunts are in front of buildings (especially blocking the entrance to colleges and exam halls) and along pavements. The serpent also has an aquatic mode whereby it will split into two ore more sections and float down the river on boats (or PUNTS). The strain can be great on the creature, and so the individual sections may wail repeatedly, especially if it sneses that people are trying to revise nearby

An unusual fact about Cambridge out of term-time that I noticed the other day. Cambridge must be the only city in the world where, when about 10,000 inhabitants ar removed from it, the number of people on the streets doubles.
Hence: either most of the inhabitants of Cambridge are actually anti-people, and therefore the business of the streets varies inversely with the number of people, or rather anti-people, on them, as the anti-people cancel out any real people who might happen to wonder by; or, alternatively, the permanent residents of Cambridge must really, REALLY hate the students, and never leave their houses when their around.
I wonder which it could be?

Almost certainly the latter