Everyone has a good reason to travel to Europe. The region literally has all the elements just about any traveller is looking for. If you can't find a good excuse to visit this incredibly diverse part of the world, then make one up.
History, culture, art, architecture, food...(oh the food), wine (largest producing region in the world), mountains, beaches, sport and the people...a heady and eclectic mix that lures millions of visitors every year.
Europe is also gifted incredible cycling opportunities. Follow the banks of the Danube through the 2nd most countries in the world, or scale the peak of the French Alps aka the Tour de France. Europeans are cycling sympatico, so even on urban roads car traffic will be friendly. The continent is also blessed with the EuroVelo cycling network. An incredible spiderweb of signposted cycling routes across Europe.