Construction is continuing at Zoo Knoxville, and when this round is complete two species of primates will have new habitats.

“We are standing in front of construction for Asian Trek phase two, which is comprised of Gibbons Trails and Langur Landing," said Lisa New, Zoo Knoxville's executive director.

White-handed Gibbons arrived at Zoo Knoxville in the 1990's, but this will be the first time Silvered-leaf Langurs will call the zoo home.

"We’ve never had that species of Langur before and to have a new species of primates - which are always so popular with the guests - plus ones that need conservation work is really a win-win for us,” said New.

WATCH: Peek-A-Zoo week takes you inside Zoo Knoxville

Currently, Zoo Knoxville is home to two Gibbons. The oldest is a female named Nipper, and she is part of the first Gibbon group brought to the zoo. The other is a male named Georgie.

In the wild, Gibbons are found in Indonesia, Laos, Malaysia, Myanmar and Thailand. They are listed as endangered.

New says the new habitat will be able to show off these animals in a way that's "completely new" for Zoo Knoxville.

“Something we’ve never done before is a suspended in the air tunnel system for the animals," said New. "The Gibbons can go there, the Langurs can go there. They can't be there at the same time, but it allows a lot of opportunities to let the animals have choice.”

The tunnel system will circle a courtyard area, which sits next to the newly completed "Tiger Forest."

READ: Tigers settling into their new home at Zoo Knoxville

Traditional indoor/outdoor habitats for the Gibbons and Langurs will sit on the west and east end of phase two of the Asian Trek. There will also be more restrooms, a new indoor restaurant, a three-story tree house and a suspension bridge.

“What's really cool for our guests is that they can be on the suspension bridge up in the treetops as the Gibbons are sailing through their system. Or, they can be on a lower level and have the Gibbons travel above them. So it's a really dynamic and immersive and that’s happening with some of our most popular animals,” said New.

The tree house is designed to feel like guests are "up in the trees." It will feature cargo netting for kids to climb on, and provide an aerial view into Tiger Forest.

“It is exhibiting animals in a way that we have never done here before at Zoo Knoxville. It's really modern zoo architecture, modern zoo exhibitry and modern zoo programming that goes with it,” said New.

The architecture will be similar to the designs seen now in Tiger Forest.

MORE: Thousands visit new Tiger Forest at Zoo Knoxville

“The response has been really wonderful. We've had people say they’ve never had encounters like that with a tiger before," said New. “People love the architecture and the play spaces for kids but there’s nothing like the moment when the tiger sees you through the glass and vice versa. People really like it and they’re curious about everything that’s in construction and what’s coming next year."

New says phase two of Asian Trek is set to open in Spring 2018.