The Rhine River is one of Europe’s busiest rivers and for tourists one of the main Rhine attractions is the castles. There are over 40 castles on the Rhine many of which are now hotels, restaurants, and museums. There are lots of castles for sale some of which are around $300,000 USD. There are some that cost even less but most of the costs start after it is purchased. It's not cheap to maintain a castle. Consider additional expenses like gardening, personnel, structural maintenance and heating, and air-conditioning. As a ballpark estimate, assume these costs will run at least $5,000 to $10,000 a month. Consequently, most castle owners go to Plan B and offer tours, home stays, and a setting for events.
A Rhine cruise offer the opportunity to visit many castle and travelers can also relax and enjoy the view of the castles as they slowly cruise by. Many of the towns and cities grew around the castles. The peasants who worked at the castle were often given a strip of land on the manor to farm which led to small towns some of which grew into cities. The peasants were expected to do the farming, road building, clear the forests, and any other work determined by the lord of the land. They planted the many vineyards along the way.
Heidelberg Castle is a ruin in Germany and the icon of Heidelberg.
The castle ruins are among the most important Renaissance structures north of the Alps. The castle has only been partially rebuilt since its destruction in the 17th and 18th centuries. It was destroyed by lightning in 1764 leaving it permanently uninhabitable and the citizens of Heidelberg had used the castle stones to build their houses. The castle is a combination of several buildings surrounding an inner courtyard. Each building highlights a different period of German architecture.
Each castle has its own story. Katz (cats) Castle was built in the second half of the 14th century as bastion and military base to protect the Rheinfels Castle. Together they formed a fortified bulwark with a barrier for levying of the Rhine toll. Due to the location on the mountain ridge Katz Castle could not be conquered from the valley. But, like all castles it went through several seizes including one in 1806 when Napoleon blew up Katz Castle. Katz Castle is now the privately owned Hotel Katz Castle.
Schönburg Castle was first mentioned in history between the years
911 and 1166. It was one of the very few medieval castles in which, after a duke’s death, all of the sons became heirs to the castle and not just the eldest which was customary at that time. Schönburg Castle was destroyed and in ruins for two centuries until, in the late 19th century, an American of German ancestry, Mr. Rhinelander, bought the castle from the town of Oberwesel and invested two million Gold Marks into the restoration. The town council of Oberwesel acquired the castle back from Mr. Rhinelander’s son in 1950. Since 1957 the Hüttl family lives at the castle on a long-term lease and established a hotel and restaurant.
Stolzenfels Castle is another castle within the UNESCO World Heritage "Upper Middle Rhine Valley.” In contrast to many other castles it was not designed to collect tolls or as a fortress. It is an outstanding example of Rhine Romanticism and has been used as a summer residence. Each castle is different with its own unique back story.
The Rhine River is one of Europe’s busiest rivers and for tourists one of the main Rhine attractions is the castles. There are over 40 castles on the Rhine many of which are now hotels, restaurants, and museums. There are lots of castles for sale some of which are around $300,000 USD. There are some that cost even less but most of the costs start after it is purchased. It's not cheap to maintain a castle. Consider additional expenses like gardening, personnel, structural maintenance and heating, and air-conditioning. As a ballpark estimate, assume these costs will run at least $5,000 to $10,000 a month. Consequently, most castle owners go to Plan B and offer tours, home stays, and a setting for events. 
