VIA RITZAU - Nov 10 - Dating.dk, Denmark's largest dating site, invites all singles in Denmark to its online Singles' Day event which is today (Nov 11th) to celebrate the Singles' Day. The event is called "What is love", it's free, and starts at 5pm. Singles' Day was invented in China, where the day was originally an occasion for singles to meet each other. The participants can meet sexologists, behavioral experts and couple therapists. There will be fun quizzes, competitions and the opportunity to meet other singles.