The glasshouse contains streams, ravines and waterfalls

Bosses at the 180-acre site, which houses Europe's biggest single span glass dome, revealed 184,000 people had already visited the centre.

"When we saw we were doing so well in the summer we revised up our estimate to 175,000 - and we've beaten that too," said spokeswoman Oenone Still.

"The visitor figure at the moment is 184,000 - we have had an absolutely phenomenal response.

"Last month the Society of American Travel Writers held their annual meeting in Cardiff and they all came down for a visit.

"They left absolutely enthused by what they had seen and said they would be writing about the botanical garden for publications across America.

"Last month during the school half-term break we had families queueing outside waiting to get in.

Sharp contrast

"Many people realise this is the first national botanical garden established for many years and they want to see what it is like from the outset.

"According to market research we have carried out, 87% of visitors said they would be back - half of those inside a year."

It is in sharp contrast to a second flagship Lottery scheme in Wales, which closed on Sunday.

The �9m Centre for Visual Arts opened in Cardiff's revamped former library in September 1999 but closed just over a year later after failing to reach its visitor targets.