The Children’s Museum & Theatre of Maine is less than $1 million from completing fundraising for a new 30,000-square-foot facility, after receiving $500,000 gift from Maine philanthropists Peter and Paula Lunder.

In announcing the gift Monday, museum officials said the new building under construction on Thompson’s Point in Portland – twice as big as the existing one on Free Street – will open in the spring.  It remains on schedule for an early 2021 opening, as had been announced before the pandemic hit. Interior walls were finished recently, and most of the interior construction should be finished by the end of the year, said Patricia Erikson, director of marketing and communications for the museum. The total fundraising goal for the new building is $14 million.

Exhibits for the museum are being built by manufacturers around the country and will be installed early next year, in time for a spring opening, said Erikson. Giant aquarium tanks, lifted by cranes, should be installed before the building is sealed up for winter, she said.

The $500,000 gift from the Lunder Foundation will be used as part of the museum’s endowment. The museum will name an arts workshop and culture exhibit space The Lunder Arts and Culture Gallery, which will house various programs put on by educators, visiting artists and community partners, according to a news release from the museum and theater.

Peter and Paula Lunder are former Waterville residents and long-time financial supporters of Maine cultural institutions, including the Colby College Museum of Art, the Lunder Institute for American Art at Colby College, the Portland Museum of Art and the Maine College of Art. Peter Lunder is a former president of Dexter Shoe Co. and a nephew of the late Harold Alfond, Dexter Shoe’s founder and a major Maine philanthropist.

“This project is for the next 100 years. The gift is to support future generations of young people who will find delight and learn so much at the newly reimagined Children’s Museum & Theatre of Maine,” the Lunders said in a statement released by the museum. “Parents will be very glad to have such a great museum where they can take their children to see, play, and learn.”

Barbee Gilman, chair of the museum’s Imagine Capital Campaign, said the gift is “instrumental to the final stages” of the fundraising campaign. She said the museum’s new space will allow it to “provide greater educational experiences and exposure to the arts, both of which are so critical in the early years of a child’s life.”

The Children’s Museum & Theatre of Maine announced plans to build a new facility in 2017, with construction beginning the next year. The museum, founded in 1976, has been located on Free Street next to the Portland Museum of Art since 1993. It merged with the Children’s Theatre of Maine about a dozen years ago. The new building will be part of a retail and entertainment complex on Thompson’s Point on the Fore River, which includes an outdoor concert venue and space for large events.