How many liters of backpack should I take when traveling to Europe?

You should take the air ticket and the baggage weight allowed by your specific itinerary as your consideration criteria.

Generally, the checked baggage of an air ticket is 20 or 25 kilograms, and the hand baggage is 5 to 10 kilograms, which means that all your luggage can't exceed 25 kilograms.

If your trip is to change places every day and you are used to "backpacking" and "free travel", I suggest you take a 20 kg backpack and then a small bag that doesn't take up too much weight. Large backpacks can be checked, usually carried on the back, and it is also convenient to put them at the front desk of the railway station or hotel. If necessary, you can take the small bag out to pack things, or you can take it on the plane.

If your trip is relatively easy, and you have to stay in the same hotel for several days in each city, or be accompanied by a bus all the way, it is suggested that you bring a wheeled suitcase with about 20 kilograms of luggage, and a notebook with less than 5 kilograms to hold more important things, such as cameras, computers, documents, food and water needed during the trip. The quality of wheeled luggage must be good, because sidewalks in many European countries are made of small bricks, especially in the old city scenic spots, where almost all streets are made of small bricks. This practice is beneficial to drainage, but it is easy to cause uneven ground and severe wear of luggage wheels. It is also very painful for girls to walk in high heels.

My bitter experience is that last year, a brand-new box was "cut" by a small brick road the next day after going out, and the left front wheel 1/4 made me walk with it unbalanced for a whole week. If high heels are not "square heels" or "wedge heels", they can't be worn at all, especially those with bad eyes. When you walk into the street, you will get all kinds of cards. After returning home, the original beautiful leather or pattern on the heel will be scratched or scratched. Pain!