The Grade II-listed building in Sefton Park, Liverpool, has reached the landmark figure since it was restored and brought back into use.
Ten years ago this September, the glass structured building was reopened to the public after it had fallen into disrepair during the mid-1980s.
To celebrate its reopening, The Palm House Preservation Trust is holding a series of stories on Thursday night told by those who were part of its successful restoration.
The building is owned by Liverpool City Council and the trust is responsible for the promotion and management of events which take place throughout the year at the Palm House.
Elizabeth-Anne Williams, director of The Palm House Preservation Trust, said: "During the 1980s the building fell into disrepair and the council was struggling to keep on top of its maintenance so had to close it.
"Two people from the community founded the Save Our Palm House campaign and put a banner around the building with those words bright and clear on it which really stirred interest and got local people together to back the campaign.
"The campaign was then formed into Friends of Sefton Park Palm House, run by a group of local people, which then led to the council letting them stage events after it had removed all the glass from the structure and made the building safe. Plants were placed in the building and it was done as a test really to see if it attracted interest.
"Friends of Sefton Palm House then became known as The Palm House Preservation Trust which was formed in 1996 and the trust managed to secure funding in 1998."
A total of £3.5m was secured through contributions from the European Regional Development Fund of £110,000, English Heritage, £300,000, and a £1.9m grant from Heritage Lottery Fund, with the trust and council contributing the rest.
Previous work carried out by a Sefton Park Palm House advisory group and the trust when it was known as Friends of the Palm House, helped with funding initiatives such as arranging sponsorship of a pane of glass and an events programme to help raise finance and the profile of the building.
Two years after all grant funding had been secured, a consortium consisting of construction firm VHE and Shepley Engineers, a subsidiary of Renew Holdings, started incorporating office, storage, toilets and kitchen areas, in a new basement area into the original space of the building.
The team worked on maintaining the original 1896 design by Edinburgh firm Mackenzie & Moncur and managed to gain access to upper roof levels for the first time in over 40 years.
The Palm House was previously restored in the late 1950s after being destroyed during the 1941 World War Two Blitz.
Williams added: "I was appointed to the trust in November 2000 as director and had to get a team together to make the project sustainable. It was a huge learning curve and it was difficult to put a business plan together because there was nothing similar or any other model like it around.
"Following its reopening on 6 September 2001, the venue has been a huge attraction for corporate parties, weddings dinner parties, and children's events. The trust has three full time staff and four part time staff as well as a board of trustees.
"We have 80 events a year so it keeps us really busy and we have to raise in excess of £300,000 a year to keep the building open which is raised through our own operations. There is no grant support."
The trust said more than 500 hundred events for visitors have taken place at the Palm House in the last ten years and it has worked with over 120 different groups and communities during the period.
The trust added that over 1,000 people have also been married in the visitor attraction since 2001.
The Palm House, which was a gift to the city from newspaper owner Henry Yates Thompson in the nineteenth century, is open free to the public every day between 10am and 4pm except during private functions.