One Of The Best Border-Busting Day Trips In All Of Europe, Per Rick Steves

London, England, is one of the most visited cities in Europe and justifiably so. There's no shortage of cultural and historical attractions, the city's culinary scene isn't shabby either, and it isn't too far from one of the U.K.'s best beaches. However, if you're looking for an adventure to add to your London itinerary, European travel expert Rick Steves has a suggestion: Consider a day trip to Paris. One of the most wondrous things about Europe is the ability for visitors and locals alike to travel with ease from one country to the other. This is thanks to the continent's rail transport system. 

With that said, travelers can catch the Eurostar, a high-speed train, from London's St. Pancras International Station to Paris' Gare Du Nord. Impressively, the Eurostar traverses the English Channel via an underwater tunnel. On his website, Steves explained, "This journey between two of Europe's greatest cities is almost as fun as the destination. At 190 mph, the train is so fast that when the tracks parallel the highway, the cars look as if they're standing still."

The best part? The trek from London to Paris is less than three hours. At the time of this writing, the earliest train leaves London at 6:01 a.m. and the last train departs from Paris for London is at 9:11 p.m. In other words, if planned accordingly, travelers truly have all day to explore Paris.

Like London, Paris is brimming with adventures. If you need guidance on what to see and do on a day trip, Rick Steves has you covered. On his website, he says that if you only have one day in Paris, head to the Louvre. The renowned museum is home to legendary works of art like the Mona Lisa and the Venus de Milo, both of which can be found in the Denon Wing. It's no wonder that Steves says this is one of the best places to visit in Europe if you're an art lover.

The Louvre is closed Tuesday but is otherwise open at 9:00 a.m. from Wednesday to Sunday. Naturally, sightseeing is a must. In fact, this is how Steves advises travelers to start their Paris day trip. He recommends they opt for his historic Paris walk and audio tour of Île de la Cité and the 5th and 6th arrondissements. Stops include Notre-Dame, Shakespeare and Company, the Latin Quarter and more. The audio tour is free to download on Steves' website.

If travelers work up an appetite, they can shop for a scenic picnic like a local at Steves' favorite street in Paris, Rue Cler. Afterwards, they can have a picnic at the Eiffel Tower and end the trip with an elevator ride up the structure for unforgettable panoramas of the City of Light. Alternatively, visitors can also visit Place du Trocadéro for views of the Eiffel Tower.

Of course, if you're vacationing in Paris, you can also do a day trip to London. Hop on the Eurostar at Gare Du Nord and you'll be in London's St. Pancras International Station in no time. Wondering what to do during your brief time there? On his website, Rick Steves suggests that your itinerary doesn't have to break the bank. He recommends one of London's many free attractions like the British Museum, Tate Modern, and Hyde Park. Steves also suggests visiting the Tower of London or Harrods, an opulent department store. 

Regardless of whether you do a day trip to Paris or London, here's what you need to know about riding the Eurostar. Given that you are traveling to and from another country, you can expect airport-style security at either train station. However, Eurostar is not stringent about liquids or food. Feel free to bring anything you want to drink or eat with you on the train. If you get hungry, the trains do have cafes onboard that sell sandwiches, drinks, and snacks. 

Note that travelers are allowed two pieces of luggage, one of which should be a personal item. Most importantly, be on time for your train. The earlier you arrive the better if not, you risk your gate closing and being left behind. To book tickets, head to Eurostar's website. And if you still need inspiration beyond a London-Paris connection, Steves also knows the best days of the week to avoid visiting Versailles.