A small nature reserve on the southern side of the Johannesburg Botanical Gardens, Melville Koppies has guided ecology walks; 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 reserve a special three-hour tour with them by booking ahead.
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