Marks grew up in Manchester, England, and studied languages. A journalist since 1984, her first job was at the Reuters news agency; she has also worked for "The Daily Telegraph". She has covered the 1999 East Timorese crisis, the 2002 Bali nightclub bombings, the insurgency in Aceh (a civil war in Indonesia), the Indian Ocean tsunami in 2004, and the 2006 Yogyakarta earthquake.