Marko's specialties are music, history and the art history of The Netherlands. He was a vip-guide, lecturer and writer for the Rijksmuseum for 14 years and appeared in various art programs on tv and radio. He published several books on the art history of Amsterdam and its museums. Marko holds a Masters Degree in classical music and gave numerous musical lectures and introductions in the Royal Concertgebouw. He also was a choral conductor and theatre docent at the cultural department of the University of Amsterdam.