NIAGARA FALLS – The invasive plants have been removed from Luna Island. Elevators at the Cave of the Winds installed many decades ago have been replaced. Three Sisters Islands will have defined overlooks with views of the Niagara River.

Crews are finishing up about $5 million in rehabilitation work at Niagara Falls State Park, part of a $25 million multiyear effort to spruce up an international tourist destination that parks officials admitted had become worn out and neglected.

“The improvements are the first in a generation and will allow our visitors to have a truly first-class experience,” Pete Gallivan, a spokesman for Gov. Andrew M. Cuomo, said.

The improvements come just as Niagara Falls, N.Y., and Niagara Falls, Ont., were ranked No. 8 on AAA’s Top 10 list of Memorial Day weekend destinations.

The improvements also will be welcome news to many residents who have long complained about conditions at the park, including some who cited criticism of the park’s condition by a New York Times travel writer and a nonprofit agency in 2011.

The criticism led state officials to announce in April 2012 a plan to “transform the landscape” of the nation’s oldest state park, which was designed by Frederick Law Olmsted.

With work on the Cave of the Winds completed earlier this month and projects at Luna Island and Three Sisters Islands slated to wrap up early next month, officials are ready to show off the improvements as the summer tourist season officially kicks off this weekend.

Here’s a look at the three areas that received the most recent upgrades:

Cave of the Winds

Before it opened for the season May 9, the popular attraction got a $1.7 million face-lift.

What was a dark and dingy hallway leading from the elevators out into the Niagara Gorge is now brighter and shouldn’t drip water on visitors’ heads anymore.

Officials also put a new railing in the hallway to separate customers entering and exiting, rather than dividing it in half with caution tape. New elevators were installed, said officials from the state Office of Parks, Recreation and Historic Preservation.

Additional improvements are planned to the Cave’s pedestrian plaza, focusing on enhanced open-air seating and expanded visitor services. They include new furniture, more trees and increased restroom capacity.

Luna Island

About $1.2 million in work is being done. One of the goals is to give visitors a more defined area where they can enjoy the views.

In addition to removing invasive plant species from the small island, which sits between the Bridal Veil Falls and the American Falls, there will be a new railing and large boulders to sit on.

The work was done by Mark Cerrone Inc. of Niagara Falls.

Three Sisters Islands

These islands, on the southwest side of Goat Island, are receiving $2 million in upgrades. The islands and their trails are being made accessible to the disabled, to comply with the Americans with Disabilities Act.

One of the main improvements is providing more established overlooks on designated trails.

Rehabilitation work has been done to the bridges linking the islands, and parking spots have been added nearby, including handicapped parking.

Invasive plant species also have been removed from the islands.

As part of the parkwide plan, all trolley stops are being replaced. The stop at Three Sisters will be the first one completed.

Scott Lawn Yard of Sanborn is the contractor for the improvements at Three Sisters.

“The work that is being done is truly spectacular and will serve to bring back the vision of Olmsted to this park and really give patrons a sense that they are in a very special place,” said Gallivan, Cuomo’s spokesman.

The head of Niagara County’s tourism promotion agency said he welcomes the improvements at the park, which will help both visitors and the “overall tourism product” of the Falls.

“Any improvements to the crown jewel of the state parks” will enhance the experience visitors have, said John Percy, president and CEO of the Niagara Tourism and Convention Corp.

The work at Luna and Three Sisters is expected to be completed in early June, according to the Parks Office.

Funding to cover the $25 million park project is coming from advanced payments of the parks agency’s Niagara River Greenway funding.

Under a deal with the New York Power Authority for the relicensing of the Niagara Power Project, the parks agency was to receive annual payments of $3 million for 50 years.

In exchange for receiving the $25 million payment now, the agency will receive $1.5 million in annual payments for the next 20 years.

After the Memorial Day holiday, work is scheduled to begin on the first of three phases of improvements at the park’s Prospect Point.

The main viewing area of the falls on Prospect Point will be closed during the summer as part of the first phase but is expected to open in the fall. Work is scheduled to be completed on the rest of the Prospect Point area by August of next year. The estimated cost for the work is $5.2 million.

Upgrading the falls

$5 million spent this season

• The Cave of the Winds will have new elevators, railings and furniture, and a brighter hallway will no longer drip water on tourists.

• Luna Island gets new railings and boulders where visitors can sit to view the falls.

• The bridges to Three Sisters Islands have been rebuilt and new overlooks, trails and parking spaces added.