For those looking to see the world and give back at the same time, consider these must-see destinations. As Cathy and Don McCallum reached retirement in 2007 – she was a teacher, he was a banker – they began thinking about what they should do after they stopped working. The North Bay, Ontario, couple knew they wanted to travel, but they didn’t just want to sit on a beach or do the usual sightseeing. They’ve always volunteered in their community...