Ahh, romance! In fiction, as in life, it takes many forms. Contemporary romance can be comfortable and familiar. It might begin simply, such as: two people, vying for possession of a dryer at the local laundromat. They argue, they talk, they make up over a cup of coffee, and then they find that opposites really do attract. Or, as in romantic suspense, it can add another dimension to your standard thriller: she's a cop, he's the suspect with a mysterious past and eyes she can't forget... and a killer is out to finish them both, if they can't resolve their differences.
Historical romances can span many places and times: medieval Scotland, Qin dynasty China, the American Old West, and Renaissance Venice, just to name a few. (There's even a subgenre for time-travelling lovers!) The rarefied society of Regency London is one of the most popular historical settings: a rakish viscount, an intriguing young debutante, a crowded ballroom... and the forbidden waltz that brings them together.