Castle Lubov was a castle mentioned by Jonathan in the film Hotel Transylvania. It is the former residence for the family of Dracula; it was burnt in late 19th century and the ruins are still there in modern days.
Count Dracula used to be a lonely vampire until he met Martha; they fell in love deeply and then they settled down in the castle. There, they had a child Mavis, who was born in 1894. But soon after her birth, the castle was surrounded by angry villagers because they found that the family are vampires. Dracula told Martha to hide with their daughter, but she was killed. Then, Dracula fled with Mavis and the castle was burnt down by the mob. Few years later, Hotel Transylvania was built and it became his new residence and a fortress for monsters.
As time goes by, however, the incident becomes a romantic story. Legend has it that the lonely count met a lady, who is known as the Lady Lubov, and they had a child; the story is still pretty similar but some things are changed: it's said that the family died in a mysterious rather than being deliberately killed by an angry mob (as well as the fact that it was only the wife who died). One hundred years later, as of when Jonathan visited the ruins of the castle, the legend is still popular; Jonathan felt that as if the souls are still there, not knowing the truth that it was only Martha that died.