A small nature reserve on the southern side of the Johannesburg Botanical Gardens, Melville Koppies has guided ecology walks, and many of the guides are members of the local botanical society and can introduce you to the rich diversity of Highveld flora found here. Bird-watching is also excellent: expect to see more than 200 varieties of grassland and Highveld birds, as well as suburban garden species and small mammals. An archaeological site contains a furnace dating from the Iron Age. The reserve is managed by volunteers, and you can take a three-hour tour with them by booking ahead. Don't go alone, as it isn't safe to do so.
Judith Rd., Johannesburg, 2195, South Africa