San Antonio Mayor Julian Castro evoked the experience of his immigrant family and their belief "that opportunity created today would lead to prosperity tomorrow" in the keynote address at the Democratic National Convention here in Charlotte.

Castro talked about his Mexican-born grandmother, Victoria, who worked as a maid, cook and babysitter in the United States and taught herself to read and write in English and Spanish.

Victoria worked hard, Castro said, "to give my mother, her only child, a chance in life, so that my mother could give my brother and me an even better one."

Castro, who was presented by his twin brother Joaquin, said that his grandmother's generation and earlier ones "always saw beyond the horizons of their own lives and their own circumstances."

"The roads and bridges they built, the schools and universities they created, the rights they fought for and won - these opened the doors to a decent job, a secure retirement, the chance for your children to do better than you did," the mayor said.

Castro, a rising star in the Democratic Party, mentioned the Republican Party convention held last week in Tampa, where he said that he heard "a few stories of individual success."

"But the question is, how do we multiply that success?" he asked rhetorically.

"The answer is President Barack Obama," he stated to a huge ovation from the crowd gathered in the Time Warner Cable Arena.

Castro said that this election will be decided between a Democratic option supporting investment in education as the road to a more prosperous economy, where taxes are not raised on the middle class and everyone pays "their fair share," and a Republican one where "millionaires can pay less" and the government "rewards companies that ship American jobs overseas."

"We know that in our free market economy some will prosper more than others" Castro said. "What we don't accept is the idea that some folks won't even get a chance."

In reference to the platform of Republican candidate Mitt Romney and his running mate, Paul Ryan, the mayor said it "dismantles what generations before have built to ensure that everybody can enter and stay in the middle class."

"When it comes to getting the middle class back to work, Mitt Romney says, 'No.' When it comes to respecting women's rights, Mitt Romney says, 'No.' When it comes to letting people marry whomever they love, Mitt Romney says, 'No.' When it comes to expanding access to good health care, Mitt Romney says, 'No.'" Castro said.

"In the end, the American dream is not a sprint, or even a marathon, but a relay. Our families don't always cross the finish line in the span of one generation. But each generation passes on to the next the fruits of their labor," Castro told the convention. EFE