Conversation so far:
When did they start the correspondent segments?
CANNOTANSWER.
Who did they interview?
current news stories and conduct interviews with people related to the featured issue.
What kind of issues did the interviews relate to?
Topics have varied widely; during the early years of the show they tended toward character-driven human interest stories such as Bigfoot enthusiasts.
Are there any other interesting aspects about this article?
John Oliver traveled to South Africa for the series of segments "Into Africa" to report on the 2010 FIFA World Cup.
In March 2012.

Question: How long was he in Africa?
Self-contained rewrite: How long was John Oliver in Africa?