Scotland is a well-developed tourist destination, with tourism generally being responsible for sustaining 200, 000 jobs mainly in the service sector, with tourist spending averaging at PS4 bn per year. Tourists from the United Kingdom make up the bulk   of visitors to Scotland. In 2002, for example, UK visitors made 18.5 million visits to Scotland, staying 64.5 million nights and spending PS3.7 bn. In contrast, overseas residents made 1.58 million visits to Scotland, staying 15 million nights and spending PS806 m. In terms of overseas visitors, those from the United States made up 24% of visits to Scotland, with the United States being the largest source of overseas visitors, and Germany (9%), France (8%), Canada (7%) and Australia (6%), following behind. Scotland is generally seen as clean, unspoilt destination with beautiful scenery which has a long and complex history, combined with thousands of historic sites and attractions. These include prehistoric stone circles, standing stones and burial chambers, and various Bronze Age, Iron Age and Stone Age remains. There are also many historic castles, houses, and battlegrounds, ruins and museums. Many people are drawn by the culture of Scotland. The cities of Edinburgh and Glasgow are increasingly being seen as a cosmopolitan alternative to Scotland's countryside, with visitors year round, but the main tourist season is generally from April to October inclusive. In addition to these factors, the national tourist agency, VisitScotland, have deployed a strategy of niche   marketing, aimed at exploiting, amongst other things, Scotland's strengths in golf, fishing and food and drink tourism. Another significant, and increasingly popular reason for tourism to Scotland -- especially by those from North America-- is genealogy, with many visitors coming to Scotland to explore their family and ancestral roots. For Chinese students, the best time to visit Scotland is in   _  .
the Spring Festival the winter vocation the summer vacation any time