Viewfinder competition: win a £150 hotel voucher

This city has hosted the Olympics, or part of them, twice. Photograph: PR It’s renowned for its peacefulness but one of the 20th century’s most infamous unsolved murders took place here; in fact the whole region is now well-known for crime. Photograph: PR A celebrated group of citizens conquered Europe, and later the world, in a foreign tongue. Name the city. Photograph: PR This week’s winner will receive a £150 voucher from Hotels.com which can be used at more than 120,000 places to stay across the world, from quirky B&Bs and family bolt holes to boutique hotels. Hotels.com customers can get a night free for every 10 stayed with its rewards scheme. Email your answer by Thursday 26 July to [email protected] or send a postcard, with address and phone number, to Viewfinder, The Observer, Kings Place, 90 York Way, London N1 9GU. ■ Last week’s answer was Wellington, New Zealand. The winner was Marie Beaumont from Bradford. Photograph: Alamy