With a population of over 728 million people in over 50 countries, Europe has a diverse culture and climate from the hot mediterranean countries in the south to the cold Iceland, Nordic countries and Russia in the north. Although its possible to drive from Ireland in the west to Kazakhstan in the east (you would need to take a ferry crossing for part of the journey from Ireland to the UK), the journey could take you 2-3 days by road. Europe has been opened up to the cheap flight market with airlines such as Ryanair, Flybe, Easyjet and bmibaby to name a few flying across the continent.
These budget airlines give passengers the opportunity to fly from one end of Europe to the other and get change from 100 British Pounds (about 150 euros). As these airlines often fly to some of the lesser known airports (to keep costs down low), the cheap flights have opened up the tourist industry to areas that wouldn't traditionally have received those types of visitors. Major cities such as Paris, London, Amsterdam, Madrid, Zurich, Berlin etc have excellent flight links to the rest of Europe as well as the rest of the world. The mediterranean countries such as Spain, France, Greece, Italy, Cyprus and Turkey are popular holiday destinations and eastern block countries such as Poland, Czech Republic are being popular destinations for British travellers with accomidation costs low and there being plenty to see and do.