Hadrian's Wall marks the Roman Empire's northernmost boundary, and at one point is less than a mile from today's border between England and Scotland. Ari Shapiro/NPR hide caption

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Britain's Prime Minister David Cameron speaks at a news conference in London on Friday after the U.K. raised its terror alert level. Paul Hackett/PA Photos/Landov hide caption

itoggle caption Paul Hackett/PA Photos/Landov

Marina Litvinenko, the widow of former Russian intelligence officer Alexander Litvinenko, says she is "relieved and delighted" with the U.K. government's decision to open a public inquiry into the former KGB agent's death in 2006 by radiation poisoning. Matt Dunham/AP hide caption

itoggle caption Matt Dunham/AP

Actress Angelina Jolie and British Foreign Secretary William Hague brought together representatives from more than 100 countries for the London conference on sexual violence in conflicts. Peter Macdiarmid/Getty Images hide caption

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The Rock of Gibraltar, as seen from the Spanish town of La Linea de la Concepcion, at Spain's southern tip. Gibraltar has been British territory for 301 years, but many Spaniards want it back. Fresh squabbles over fishing rights cropped up recently. Lauren Frayer/NPR hide caption

itoggle caption Lauren Frayer/NPR

The U.K. supports stability and democracy in Ukraine, says British Foreign Secretary William Hague, who visited NPR headquarters in Washington, D.C., Wednesday. Jim Tuttle/NPR hide caption

itoggle caption Jim Tuttle/NPR

Priscilla Smithers and her four children have arranged chairs around a few air mattresses to create a space for themselves, after fleeing their home. Ari Shapiro/NPR hide caption

itoggle caption Ari Shapiro/NPR