The city of Reykjavík, Iceland, uses hot water to maintain the temperature of a section of its downtown pond so the birds living there always have a corner in which to swim, even in winter.
Pet dogs were banned in Reykjavík, Iceland for sixty years. Even today, owning a pet dog there requires special permits, hence cats are the pet of choice. The dog ban was issued in 1924, at a time when the population of Iceland was overwhelmingly rural and Reykjavík was still a small, but rapidly growing fishing town. Reykjavík was facing an acute housing shortage at the time, and as people lived in overcrowded apartments the city authorities reasoned that banning dogs would make the situation somewhat more bearable.