With 7 of the top 10 tourist nations being a part of this continent, Europe is bound to be the epicentre of all tourism on this planet. With its well preserved cultural heritage, open borders and efficient infrastructure visiting Europe is a delight. Rarely will you have to travel more than a few hours before you can immerse yourself in a new culture.
The most developed continent provides the best for everything, be it museums, parks, mountains, castles etc. I will provide you with the best tourist destinations in Europe which will make you sure you have a lifetime experience on this trip.

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Lonely Planet introduces Europe in a brilliant way:
Few places pack the punch of Europe. From its Northern Lights to its Southern shores, this drama queen keeps on thrilling, surprising and confusing with her extraordinary wealth of sights, sounds, peoples and parties. As well as the birthplace of democracy in Athens, the Forum of Rome, the renaissance buildings and art of Florence, the graceful canals of Venice and the Napoleonic grandeur of Paris, there's always the less expected sites such as the Moorish palaces of Andalucia, the remains of one of the Seven Wonders of the World in Turkey, the majesty of a second Venice in St Petersburg and the haunting buildings of Auschwitz in Poland.
(Source: Lonely Planet)
One of the most visually appealing countries in the world, Italy is more lovingly called as Belpaese or (Beautiful Country). Widely regarded as the birthplace of Western Culture, Italy has its distinct aura and grandeur. Its various attractions make it one of the top visited tourist countries in the world and it has the greatest number of UNESCO World Heritage Sites of any country. All in all its just the perfect way to start your vacation.

(Source: WTL photos)
No other city of the ancient world boasts of as much heritage and influence as Rome. The capital of the largest empire ever on Earth is the embodiment of culture and royalty. Located perfectly between the seven hills, visit Rome is a delight in itself.
The foremost attraction of this city is undoubtedly the Colosseum. The largest amphitheatre of its time was a symbol of strength of the Roman Empire. A walk down its history is enjoyed by all

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After visiting the Colosseum head on to the The Roman Forum . This place is sandwiched between Palatine and Capitoline hills. It was a seat of the Roman government and you can take a walk through the ruins of Arch of Septimius Severus, Temple of Saturn, Basilica Julia and the House of the Vestal Virgins.
On the next day , start your trip with a visit to the grandest church of all and home of the pope - Saint Peter's Basillica. This church is truly a visual delight with its giant dome being designed by the best artists of Italy including greats like Michaelangelo .

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Here is an excerpt from Wikipedia which sums up Rome beautifully:
Rome today is one of the most important tourist destinations of the world, due to the incalculable immensity of its archaeological and art treasures, as well as for the charm of its unique traditions, the beauty of its panoramic views, and the majesty of its magnificent "villas" (parks). Among the most significant resources: plenty of museums - (Capitoline Museums, the Vatican Museums, Galleria Borghese, and a great many others)aqueducts, fountains, churches, palaces, historical buildings, the monuments and ruins of the Roman Forum, and the Catacombs.
(Source: Wikipedia)
The second most populous city of Italy, Milan is also known as the fashion capital of the world. A paradise for shopping, football, opera, and nightlife, Milan is a great city to visit with your special someone.
Start your day with a visit to the majestic Duomo or the Cathedral of Milan. This church is the seat of Arch-Bishop of Milan and took almost 500 years to build. Its Gothic styled cathedral is the fourth largest in Europe and the second largest Catholic cathedral in the world.
(Source: eblaser)
Next up would be the "Last Supper". Any visit to Milan or for that matter Italy is incomplete without seeing this masterpiece. Painted by no one other than Leonardo Da Vinci for his duke, this painting is housed in the Santa Maria delle Grazie church and is surely a feast for the senses.
Right after this visit head to the incredible La Scala because going to Milan and not enjoying an opera would be an absolute crime whether you like opera or not. To soak in the culture of Milan, a visit to the La Scala, the famous opera house of Milan, is an absolute must.
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And finally, Piazza Del Duomo will beautifully sum up Milan for you. This city square is located in the geographic centre of the city and is the artistic, cultural, and social centre of the city. In addition to housing the Duomo, this square houses other foremost attractions in Milan along with the finest shopping boutiques and fines restaurants.
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Here is a brief introduction about this city:
(Source: worldguides)