One of the things many visitors to Spain are bound to notice is the peculiar daily rhythm or schedule, with an afternoon siesta and really late-night schedule. One reason for the mid-day siesta might be as part of a more efficient sleep schedule, namely the "siesta" program of polyphasic sleep:
This sleep cycle is actually pretty common around the world in warmer countries such as Latin America, where the temperature is so hot during the middle of the day that people retire to take a short nap after lunch. It involves 6 hours of core sleep and one short 20-30 minute nap. You will find in these countries that most shops close during the early afternoon, as everyone is ‘busy’ taking their siestas!
The first time I visited Madrid, I remember visiting a night club at around midnight and finding it largely empty, even on a Saturday night. I was about to leave after a half hour when suddenly the crowds started flocking in, and the place was packed until 5 in the morning.
It turns out Spain's late-night schedule may have its roots in World War II, when many European countries under German control switched their clocks to synchronize with Germany.
Until the 1940s, Spain was on the same time as Britain and Portugal, which are on roughly the same latitude. But when Nazi-occupied France switched to German time, Spain's Franco dictatorship followed suit.
"The fact that for more than 71 years Spain has not been in its proper time zone means ... we sleep almost an hour less than the World Health Organization recommends," the lawmakers wrote. "All this has a negative effect on productivity, absenteeism, stress, accidents and school drop-out rates."