San Antonio Mayor Julian Castro, left, and his twin brother State Rep. Joaquin Castro give an interview during preparations for the Democratic National Convention at Time Warner Cable Arena on Monday. Streeter Lecka/Getty Images hide caption

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Final preparations were under way Monday for the opening of the Republican National Convention in Tampa, Fla. Democrats are holding their convention next week in Charlotte, N.C. Stan Honda/AFP/Getty Images hide caption

itoggle caption Stan Honda/AFP/Getty Images