More than two metres (seven feet) tall, the titan arum is the star attraction of the Meise Botanic Garden just outside Brussels.
The plant, resembling a lusty triffid, is popularly known as "Titan's penis" for its phallic shape, reflected in its scientific name, Amorphophallus titanum.
To further add to its appeal, it also stinks like rotting meat, which gives rise to another name it is known by, the "corpse flower".
That odour -- "a bit like garbage that's been left out in the sun for too long" -- is to lure insects to help it pollinate, the garden's spokeswoman, Manon Van Hoye, told AFP.
Native to the rainforests on Indonesia's Sumatra island, the titan arum flowers very rarely -- at intervals of between three and seven years.
And its colossal bloom only lasts around 72 hours.
"It's gorgeous, I had no idea it was that big," said visitor Carine Kurris.
Van Hoye said she was "a bit moved" to see the plant expose its full splendour.
"The shape is architectural, I love the colour, and I also love the story behind it, that it's endangered and that it's being protected," she said.
