The lord of the castle, a retired bricklayer, has been working on his fortress every spare minute for the past 37 years

Heinz Schoenewolf has a knight's castle in his garden. He's been building it for the past 37 years using rubble from neighbouring communities. Its grey brick-built tower in the city of Saarbruecken in south-west Germany can be seen from afar.

The district where Schoenewolf lives is an area of detached family houses and the castle draws a lot of attention. The pensioner's private fortress is just a few steps from the quiet street behind a slender iron gate.

The lord of the castle, a retired bricklayer, has been working on his fortress every spare minute for the past 37 years. Situated on a 350 square metre plot of land, his home is seamlessly joined to the castle which is built on a scale of 1:10. The facade of the house has been matched with the grey of the castle using acrylic paint.

Spiral stairs with over 100 steps in total wind through the castle's narrow corridors, around balustrades and battlements, a rain water well and toilets. The castle has high towers, several rooms and chambers, a hunters' room, an open fireplace and a wooden chapel. "The narrow corridors allow a knight to defend his fortress against foes," explains Schoenewolf. For him, the castle is a beautiful alternative world right behind his house.

The story of the castle's construction goes back to 1975 when Schoenewolf had a garage built in his garden. The soil and sand that had been pushed to one side was piled up as high as a wall. Building authorities approved the garage but urged Schoenewolf to stabilize the wall of earth and sand. They wanted a concrete wall with a minimum height of five metres.

"That would have looked awful," Schoenewolf says dismissively. At first he did build a wall, only later over time did he turn it into a proper castle. "It simply grew over the years," he says. "I just started building."

It took him years to collect the granite in the castle's walls. Some of it came from old tram tracks, which were supported by granite blocks. News quickly spread by word-of-mouth that a man was building a knight's castle. Surrounding communities collected old bricks and donated them to him for his project.

The highest point in the castle measures just over 15 metres. If he wanted, Schoenewolf could look into the neighbours' living rooms from his tower. That's no problem for Kai Werner, a lawyer with the German Tenant Association. "That's his private business. If the authorities allowed it, it's okay," he says.

Schoenewolf's neighbours have grown to accept him as just another resident who has a peculiar hobby. Occasionally he invites fellow hunters to his castle for a drink before they head out. Often he encounters scepticism and is asked if he's really serious about completing the castle. He replies by shaking his head and asking: "Well, don't you have any fantasy?"