I came across this article which gives you a lot of information on why the below destinations stand out from the rest. Please visit the Author's site to Read more as I have just tagged a tiny bit of info.
#1 in Best Places to Visit in Europe
Why go: Roma is a can't-miss spot on your European tour. The aroma of fresh Italian cooking wafts through alleys and historic sites sit at every turn. The Colosseum, St. Peter's Basilica and the awe-inspiring Trevi Fountain are essential attractions for any traveler.
#2 in Best Places to Visit in Europe
Why go: Paris is filled with iconic museums (like the Louvre and the Musée d'Orsay), monuments (like the Eiffel Tower and the Arc de Triomphe) and churches (like the Sacré-Cœur and Notre Dame). Still, save some time for drawn-out meals and relaxing at sidewalk cafes.
#3 in Best Places to Visit in Europe
Why go: Exploring the world-class British Museum, seeing a musical in the West End, touring the Tower of London and gorging on fish and chips at a local pub are all part of the London experience. However, London's high hotel prices can make budget travelers cringe.
#4 in Best Places to Visit in Europe
Why go: Venice may conjure images of romantic gondola rides down the Grand Canal, but this City of Water isn't only for swooning lovebirds. With an abundance of theaters, churches, historic sites and notable eateries, all types of travelers will enjoy Venice's charms.
#5 in Best Places to Visit in Europe
Why Go: Compared to Rome, Firenze gives visitors a taste of a more authentic Italy. Florence boasts renowned museums, stunning architecture and mouth-watering cuisine. You can't miss admiring Michelangelo's David and climbing to the top of the Duomo.