A miniature garden or ecosystem contained within a glass or plastic container. If sealed, self-sustaining terrariums need very little to no maintenance. Small and slow-growing foliage plants, miniature ferns and mosses are great for sealed terrariums, and succulents and cacti for open terrariums. The first example of a terrarium was a Wardian Case, which helped plant collectors bring back and introduce new, exotic plants in the 19th century.