Mauritius doesn’t have a bad side, but for natural phenomena, pick the south west. Le Morne Brabant is here, along with Seven Coloured Earths, Black River Gorges National Park, and the tallest of the island's waterfalls, Cascade de Chamarel. Tumbling from a height of 83 metres the falls look like ribbons of light and the clear pools at their base are perfect for wild swimming.
Take the well-marked trail to the top of the falls then follow the path down to the pools below. It sounds like a lot of effort, but the hike's fun and the pools are worth the legwork.