Belgium is one of the easiest countries in Europe to get around: distances are short, trains run all the time and the three most beautiful cities are on the same line.
In three days you can see the Grand Place of Brussels, the medieval castle in the heart of Ghent and the canals of Bruges, the best rated city in Europe in Wondar.
The route is:
Brussels > Ghent > Bruges
All three have the best time between April and June, with mild weather and before the summer crowds.
Brussels
Start at the Grand Place. It is the center of everything and it is advisable to see it twice: during the day, to look at the facades of the guilds and the City Hall, and at night, when it is illuminated.
A few blocks away is the Manneken Pis. It's much smaller than fame makes you think, so it's enough to pass. From there you can walk up to Mont des Arts, which has one of the best views of the center, and continue to the Cathedral of Saint Michael and Saint Gudula and the Royal Palace.
In the afternoon, the Atomium. It is outside the center and can be reached by metro. It is the structure that was built for the 1958 Universal Exhibition and next to it it has Mini-Europe, in case you are traveling with children.
On the way you will come across comic murals painted on the party walls: Brussels has dozens scattered throughout the city.
Wondar tip
Leave the Atomium for the afternoon and the center for the morning. The Grand Place fills up around noon, and early is much more enjoyable.
Ghent
Ghent is about 35 minutes by train from Brussels and is the great underrated of the route. It has a historic centre as well preserved as Bruges, but it is still a university city with a life of its own, less tourism and lower prices.
The first is the Gravensteen, the Castle of the Counts: a twelfth-century fortress planted in the middle of the city, with a moat and walls.
Then, St. Bavo's Cathedral, which houses the Adoration of the Mystic Lamb by the Van Eyck brothers, one of the most important paintings in the history of European art.
Between them, walk along the Graslei and Korenlei quays, with their facades reflected in the water, and stop at St. Michael's Bridge: from there you can see the three towers of Ghent lined up.
Wondar tip
If you want to spend less on accommodation, Ghent is the best base of the three: it is in the middle of the route, half an hour from Brussels and Bruges, and sleeping is cheaper.
Bruges
Bruges is about 25 minutes by train from Ghent. It is the city with the best score in Europe in Wondar and it is small: the entire old town is covered on foot.
Start at the Grote Markt and, if you have the physical inclination, climb the 366 steps of the Bell Tower to see the city from above. Next door is the Burg Square, with the Town Hall and the Basilica of the Holy Blood.
The boat ride on the canals takes about half an hour and is worth it: it shows the city from an angle that walking you can't see.
To close, head south to the Ten Wijngaerde Beguinage and Minnewater Park, the quietest area of Bruges. On the way is De Halve Maan, the city's historic brewery, which you can visit.
Wondar tip
Bruges receives many day trips. Arrive early or stay until sunset: when the groups leave, the city changes completely.
Practical information
Trains: All three cities are on the same line and there are services several times an hour. There is no need to reserve a seat or buy in advance.
Approximate times: Brussels to Ghent, 35 minutes. Ghent to Bruges, 25 minutes. Bruges to Brussels direct, about an hour.
Where to sleep: you can base yourself in a single city and move around during the day, or sleep one night in each one. Brussels has more supply, Ghent is the cheapest and Bruges the most expensive of the three.
If you have one more day: add a second day in Bruges, which is the one that yields the most in time.