Open this photo in gallery: Ukraine's President Volodymyr Zelensky, left, waves as he is welcomed by South Africa's President Cyril Ramaphosa during an official visit to South Africa, at the Union Buildings in Pretoria on April 24.PHILL MAGAKOE/AFP/Getty Images Ukrainian President Volodymyr Zelensky, on a historic first visit to the African continent, has asked South Africa to help rescue thousands of Ukrainian children who were abducted and taken to Russia. Mr. Zelensky handed a list of 400 Ukrainian children to South African President Cyril Ramaphosa in a meeting in Pretoria on Thursday. “We have to get everyone back,” he told...