If you want do something really romantic, if you (and your partner) are into long walks, and if you want to really immerse yourself in the atmosphere of Budapest, walking along the Danube would be a really nice choice.
I like being outdoors – so if I am romantic, I also prefer to do something in the open. It is especially true during the fall and spring when the weather is the best here in Budapest: warm but not sweltering-ly hot. The sky could be amazingly bright and blue especially along the Pest side of the Danube, when the winds keep the air as clean as possible in the middle of a metropolis.
A nice place to start a romantic tour like this would be at the National Theater. The building itself really lacks style however, there is a nice hedge labyrinth, where you can have some fun together. There is a pretty nice garden, and a nice walkway starts here along the Danube. (For me, it would be especially convenient because I live quite near this place.) From a small zigurrat you can have a pretty good view about your forthcoming journey. The promenade goes almost all the way to the Petőfi Bridge. You can find a few nice cafes too along the way.
At the foot of the Petőfi Bridge you can find the terminal station of a railway line. If you change your mind, you can take it and go to Csepel, an island district of Budapest. It is a nice mixture of various socialist architecture. For me, this place holds some really romantic memories: I used to meet with a girl here who I courted for some time; I also had a pinhole portrait shooting here with my girlfriend. You can also have a nice view from here of the Danube and of the Buda side.
Here, the promenade continues through a small park. It is a nice patch of greenery in this district. It has seen better days; you can feel some air of melancholy in the air. With the fragrance of the Danube, it mixes up to a really unique atmosphere, nowhere else to be found in the city.
The last third of the promenade is closed, a pretty nice cultural center was built here, now it cannot be opened due to some bureaucratic debates. I hope the situation will be resolved because now it not only closes out the public from this part of the bank but because the building is a pretty nice piece of architecture in itself. It would be much better to put it into use. For the time being, you should walk around the compound to reach the Szabadság (Liberty) Bridge.
Here you should walk along the streets close to the Danube: at the foot of the next bridge, the Erzsébet (Elisabeth) Bridge, there is a really nice park where you can have some rest if you wish. The renovation of this park was finished only a few years ago, now it is an excellent resting place for everyone in the inner districts.
After the Erzsébet Bridge starts the most authentically and traditionally romantic place of Budapest: the Corso. It is frequently mentioned in the early 20th century as a place to have a rendezvous between lovers. It is a beautifully kept promenade, on one side is the Danube and on the other side are hotels, restaurant, and the old building of the casino for the Officers of the Royal Army (now it is a place for conferences and cultural events). The Corso is in the oldest parts of the city, on the other side of the Danube, you can see the Castle – the old-town district on the Buda side. You can walk all the way to the oldest permanent bridge in Budapest, the Chain Bridge.
From the Chain Bridge, you can walk on a graveled trail. Here you can get real close to the river: there are many stairs going right down to the river. There are also benches where you can sit with your partner – either way, you can have an excellent view of the city.
After a while, you’ll arrive on a cobblestone road, which eventually ends in a gigantic row of stairs. As you walk next to the house of Parliament, you can see the Margaret Bridge and island – another gorgeously romantic place to visit.