The Tropical Glasshouse, which is being officially opened on Thursday, has been built within the double walled garden at the National Botanic Garden of Wales.
It has already been stocked with thousands of plants including palms, orchids, giant leaves and flowers.
Among the more unusual is the Piperales Aristolochiaceae - or Dutchman's Pipe. Its smell attracts flies and once inside they are trapped by backward-pointing hairs, causing them to thrash about pollinating the flower.
The tropical glasshouse is one of a number of attractions that have been added as part of a recovery plan following financial difficulties at the garden.
Horticulturists have visited other botanic gardens such as those at Kew, Edinburgh and Glasgow in the search of tropical plants suitable for the hot and humid atmosphere.
Work began on the tropical glasshouse 18 months ago after the garden successfully secured a further £1.35m from the Millennium Commission - taking the total Lottery funding for the site in Carmarthenshire to £22.5m.