Saudi Arabia's Neom project has announced Leyja, its fifth region, which will feature a mirrored hotel by Shaun Killa, a rock-shaped hotel by Mario Cucinella and a stepped cliffside hotel by Chris van Duijn.

The Leyja region will be located in an ancient valley that starts at the Gulf of Aqaba coast and is overhung by 400-metre-tall mountains.

Three architects have been tapped to design "luxury high-end boutique hotels" for the region, each with 40 rooms and suites, Neom said.

These will be placed along a route that follows the shape of the valley, beginning with the Adventure hotel designed by van Duijn, who is a partner at Dutch studio OMA.

The hotel will comprise a series of stepped volumes that cling to the rockside, forming cantilevered terraces and swimming pools.

Among its offerings will be a sky lounge, a wellness spa and a sky pool.

"Neom is founded on a very sustainable approach," van Duijn said in a video showcasing Leyja. "It's energy-neutral. It's carbon-neutral. The world needs to see how we can develop positive solutions for us to live in."

"Every building that is designed will be designed in respect and in balance with nature and the landscape," he added.

The Adventure hotel will be followed by the Oasis hotel, designed by Italian architect Cucinella as a cluster of geometric formations rising from the rock.

It will feature a mineral garden and hanging gardens, as well as an observation deck and a rooftop pool.

"In the last century, architecture was against nature, no?" Cucinella said. "Polluting cities, polluting people, polluting the air."

"Our work is to find again this friendship with nature," he added. "To design a building is a journey, from the dreams to the reality is the most difficult part."

Killa, of architecture studio Killa Design, will be creating Leyja's final offering, the Wellness hotel. It will comprise two vertical mirrored volumes facing each other and will have an entire floor dedicated to wellness.

Rooftop pools will crown the mirrored buildings.

"One of the greatest challenges is creating beautiful buildings that change emotion, that are timeless and sustainable," Killa said.

"It's our responsibility to build as such a light touch in the wadi that it's almost like a footprint hasn't landed."

Guests at Leyja's three hotels will be able to explore a 73-kilometre hiking trail to the Trojena ski resort, which is also being built as part of the wider Neom project, and take part in mountain and adventure sports.

According to Neom, 95 per cent of Leyja will be preserved for nature.

Neom will eventually have 10 regions in total, encompassing an area of around 10,200 square miles. It is the most high-profile and largest of the "giga projects" currently being developed in Saudi Arabia.

Four other regions have so far been unveiled. As well as Trojena, Neom will include an octagon-shaped port city named Oxagon, the mirrored mega-city The Line and an island resort called Sindalah.

The Neom project has been widely criticised on human rights grounds. Last year, human rights organisation ALQST reported that three men were sentenced to death after being "forcibly evicted" from the Neom site, while earlier this year experts from the UN Human Rights Council expressed "alarm" over the imminent executions.

Saudi Arabia responded to the UN by denying abuses had taken place.

In an opinion piece for Dezeen about The Line mega project, Dana Cuff wondered "Why would architects let themselves be so vitiated?"

The images and video are courtesy of Neom.