According to Wikipedia, Victoria Falls is a waterfall in southern Africa on the Zambezi River at the border of Zambia and Zimbabwe. If you were one of the people who watched The Amazing Race sense Episode 1 of Season 1, you may remember Victoria Falls was the first place visited in the series. This was back in 2001.
The show only went to Zambia once, and that was 14 years ago. I highly doubt that Zambia will be visited again. I believe Season 27 marks the first time visit to Zimbabwe.
Of course, a lot of people will be saying things like "But Namibia was visited in Season 2, but they went there in Season 26." True, but I don't believe the crew would visit the exact same city of the country. This is the case for many first and second time visits in countries. The first season it is visited, they will visit the capital/largest city. The second season, they will visit a small city. Therefore, they are probably visiting Zimbabwe for the first time.