Many such destinations are worth visiting for other reasons too: as well as being pleasant places to go on holiday, Iceland, Hawaii and the Greek island of Santorini all demonstrate, for example, the influence of vulcanism on island formation.

ECONOMIST: Good sport

"If you have to win this state, and if this is the state the Democratic Party set up as the example of the influence of Hispanic voters in the party, you have to be able to show you can win Hispanic support, " said Adam Segal of the Hispanic Voter Project at Johns Hopkins University.

CNN: Democrats vie for Nevada's Latino vote

The perception of the harmful effects of smoking, for example, can influence habit and addiction.

CNN: The power of perceptions: Imagining the reality you want