Claim: Emmarentia dam, which is the longest dam in the world, is about 800 meters (2624.67 ft.) and the Johannesburg Botanical Garden is on the northern part of the shore.
Evidence: The length of the dam is about 400 metres (1,310 ft) with a maximum height of 20 metres (66 ft) and a water surface of 8.8 hectares (22 acres). 
The Johannesburg Botanical Garden is on the western shore of the dam.