StonehengeApprox. Time: 3 hours
Activity Level: Easy to Moderate

More than 4,000 years ago, the people of the Neolithic period decided to build a massive monument using earth, timber and eventually, stones, placing it high on Salisbury Plain in Wiltshire, England -- about 137 kilometres southwest of London. Why anyone ever decided to build Stonehenge remains a mystery, with theories ranging from religion to astronomy. Some of what was Stonehenge still stands today, as mysterious and sacred as it must have been to the hundreds of people who helped build the site.