Portsmouth's new tropical butterfly house opens on Saturday at Cumberland House natural history museum in Southsea.
The old enclosure was demolished earlier this year and a new one was built by Portsmouth City Council, providing a better environment for the butterflies and for visitors.
The new building will be open from 3pm on Saturday 19 August. Opening hours will be the same as the rest of the museum – 10am–5.30pm, Tuesday to Sunday and bank holiday Mondays. Admission is free.
The attraction is likely to busy when it first opens, so visitors might want to wait a few days before seeing the butterflies.
Cllr Linda Symes, the council's Cabinet Member for Culture, Leisure and Sport, said: "It's wonderful to have this new attraction open during the summer.
"Seeing the butterflies at Cumberland House is a tradition for many local families, and is also part of the experience for visitors to the city.
"The new building will be a far more suitable home for the butterflies, and a more attractive place to visit.
"Demolishing the old butterfly house has also opened up the rear of the building, showing how it was intended to look.
"We're very grateful for all the enthusiasm and support we have had from the community for this project. Local people have really got behind it. We're particularly grateful to Fyffes for donating the puparium, where the butterflies hatch out, and to Tesco for funding butterfly-friendly plants."
The old building dated back to the 1980s and obscured the original view of the rear of Cumberland House. Plans to demolish and replace it were backed 100% by museum visitors taking part in a consultation last year.
The enclosure will have a range of tropical South American butterflies, hatched on-site from ethically-sourced chrysalises. The species and numbers will vary, with about 50 hatching each week.
Among the most spectacular are swallowtails, morphos, owl butterflies and longwings.
The enclosure is kept at butterfly-friendly temperature and humidity levels and has a range of plants including orchids, jasmine, banana, lemon trees and lantana. The plants provide shade, as well as food for caterpillars and adult insects.
As part of the project, the museum gardens will be planted with flowers that attract native species of butterfly.
The council has allocated £130,000 for the new building, and will ensure it is fully funded.
It has opened up the opportunity to residents to contribute to the project, using an online crowdfunding page.
The crowdfunding campaign ends on Sunday 20 August. Under the terms of the fundraising site, if the target is not met then people who made pledges do not have to donate. However, the council is looking at ways in which people who have made pledges to donate can still do so.