The Floriade horticultural show, which takes place in the Netherlands every 10 years, will open its doors to visits in Almere on Thursday.

The event was first held in Rotterdam in 1960 with the aim of strengthening the image of the Dutch horticulture sector, and to promote exports, but has since expanded into an international plant and garden show with exhibitors from other countries.

This year’s theme is Growing Green Cities, with a focus on greening urban areas and, the organisers say, 33 other countries are also showcasing their approach. Other highlights include the one hectare green house, where plant and flower competitions will take place, and a cable car crossing across the site.

However, the the event has been bogged down in controversy since its launch, and has gone way over its initial €10 million budget.

The final price tag is unclear, but the Financieele Dagblad suggests that the total cost could be as high as €200 million, and that the event will have lost €100 million when it closes. Some two million paying visitors are needed to cover the cost, local broadcaster Omroep Flevoland said. Others have put the necessary visitor numbers at 10 million to break even.

The last Floriades in Venlo, Haarlemermeer and Zoetermeer editions also lost money.

Nevertheless, the organisers and local authorities say the event does leave lasting benefits – in the case of Almere, a new park and green residential area – one reason for the high cost of the development.

King Willem-Alexander will perform the opening ceremony on Wednesday afternoon.