Bulgaria, Singapore, China

Rageh Omaar is in Bulgaria to find out why authorities are building a wall along the rugged Turkish border with the country. Lucy Watson looks at how communist China's shortage of women has created a market for foreign brides who don't require the expensive pre-wedding dowry payments that Chinese women now require. John Irvine is in Dubai's Burj Khalifa to find out more about the people who work and live there.