From the out-there kitsch of modern-day Roswell to the skyward-bound spirituality of Taos, the people of this southwest US state can’t seem to stop staring at the sky.

The badlands of New Mexico epitomise the raw, stark beauty of the Wild West. Vast mountain ranges and plateaued mesas stand impassive in the desert haze. Ragged gorges, carved out by the Rio Grande River, rip into the land like an open wound. Rows of aspen trees turn to a chemical yellow in the relentless southwestern sun, spotlighting the rolling ranches that are home to cattle and horses. And above it all, the infinite New Mexico sky, an almost physical presence pressing down upon the horizon like a paperweight.

The state of New Mexico has so much beauty that you can’t help but feel sorry for poor old Roswell, a small town in the south. The country round here is lacking almost all of the above. In fact, the only thing that Roswell country has got going for it aesthetically is… flatness. Nowhere does flatness like Roswell. The desert here is a ruler-edge sheet of mute brown dirt, studded with the occasional spiky yucca tree, and goes on and on and on, much in the same interminable way as a pub bore.

But while Roswell might not have much, what it does have is out of this world. This town is the UFO capital of the USA – perhaps the only place on Earth where aliens have actually landed. The story goes that, in 1947, a Roswell rancher named Mac Brazel came across a field of metallic debris. The metal was unlike any he had seen before; he could pick it up, scrunch it in his hand and watch it spring back to its original shape. That same day, a local undertaker received a call from a military base asking for a supply of child-sized caskets. Arriving at the hospital, he was met by a nurse who told him in a panic that she’d seen military doctors examining the bodies of a number of child-sized grey aliens with huge saucer-like eyes.

Immediately after the incident, the military released a press release confirming that there had been a UFO crash in the area. But a week later this was retracted, and another release was written, saying that the debris was simply that of a military weather balloon. It was too late. The legend of an alien landing in Roswell spread across the country, and then the world. In 1991, a museum dedicated to the incident was opened and subsequently sparked an entire alien economy in the town. Roswell has dozens of alien souvenir shops and bars selling alien beer, all capitalising on the extraterrestrial economic stimulus. Even the streetlamps have alien eyes painted on.

Mark Briscoe is the library director of the UFO Museum and, unsurprisingly, has no doubt that aliens landed here. He believes that the military covered up evidence of the landing in to order to prevent mass hysteria, but used information from the captured aliens to develop new technology. ‘In the 20 years after Roswell, humans invented more new technology than we had done in the previous 200,’ he says. ‘The iPhone 5 is more powerful than the computer we used to land on the moon! Humans are smart, but we’re not that smart. We’ve definitely had help. Probably through reverse engineering from alien technology.’

Despite Mark’s adamant stance, the museum is careful to leave all options on the table, which is a relief given the somewhat flaky nature of the evidence. One section even lists common ways by which fake photos of UFO s are made – by photographing a lit lampshade reflected through a window, hanging a hat on a string, and throwing a hub cap in the air.

Whatever the truth of the 1947 incident, there is undoubtedly something otherworldly about New Mexico. The vast space – it’s the fifth biggest state in the US, with a population of only two million – lets the imagination run free. And the infinite emptiness of the brilliant sky above means that on the rare occasions when an object, such as a plane or a hot-air balloon, does pass through, the bright contrast lends it such a fierce intensity that it confuses the eye. After spending time here, you can easily understand why virtually everyone you speak to has a story about seeing a light or unidentified shape in the sky.

But not everyone puts it down to extraterrestrial activity; other explanations are easily at hand. In the centre of the state, a four-hour drive from Roswell, lies an enormous segment of fenced-off flatland, almost devoid of population. This is the White Sands Missile Range, the perfect place for the US military to test out their latest bombs, rockets and planes without fear of upsetting the neighbours. Everything from V2 rockets – technology co-opted from the Germans after WW II and used for the first space shuttles – all the way through to modern missile defence systems has been tested here. Nearby lies Trinity, the site of the first atomic bomb trial in 1945. And New Mexico remains at the forefront of space-age technology – Richard Branson is even building his Spaceport America base here, in the hope of breaking the final frontier of space tourism.

Unsurprisingly, with all these flying explosives zooming about, access to the missile range is restricted, save for one area: the White Sands National Monument. Here, a remarkable geological quirk has turned some 275 square miles of desert into a glistening, ice-white beach. Rolling dunes of white gypsum eroded from the surrounding mountains stretch out as far as the eye can see. It looks for all the world like Arctic tundra, and if it wasn’t for the desert sun beating down, you’d be excused for putting on an extra layer before leaving the car. Walking across these pristine dunes is a mind-blowing experience – you feel like Lawrence of Arabia discovering Antarctica. And White Sands is certainly consistent with New Mexico’s ET spirit: few landscapes would look so at home on an alien planet as this.

New Mexico’s military presence provides another take on the state’s UFO mysteries. Could the Roswell incident have been caused by the misfiring of some new-fangled military equipment? That’s certainly the view of Norio Hayakawa, a Japanese-American who has spent most of the last 35 years studying the history of UFO sightings. Norio lives in the state’s largest city, Albuquerque, which manages to combine Route 66-style roadside motel culture, modern university life and a Spanish-built Old Town that looks like something straight of a John Wayne movie. Norio argues that the US government exploited the American public’s propensity for conspiracy theories and fuelled rumours of an alien crash in order to cover up what they were really doing in New Mexico.

‘UFO just means “unidentified flying object”,’ he explains. ‘UFOs and aliens are two completely separate things. I think that the association of UFOs with aliens is a brilliant strategy by the government in order to create a “laughter curtain”, so that people think you’re a crackpot for talking about places like Area 51 [a supposed alien base in Nevada]. Which is all very convenient, because it means no-one asks questions about what’s really going on.’

Albuquerque has its own version of Area 51, the Manzano Mountains in the centre of yet another military base. Norio drives me there, pointing out the electric fences that surround it. He explains that the main mountain is actually hollowed out, Thunderbirds-style, in order to store nuclear weaponry and airborne technology. Norio believes that the US military were once developing new flying machines here that were crescent-shaped, and from a distance would look like flying saucers. ‘It could have been one of those that crashed at Roswell,’ he says. ‘They didn’t want anyone to find out what they were up to, so encouraged the alien rumours.’ The idea of an alien conspiracy is thus a conspiracy itself.

And so the plot thickens. But maybe those searching for extraterrestrial beings in Roswell are looking in the wrong place. Perhaps they should start at Taos, a small but lively northern town which has become a haven for New-Age spiritualists, hippies and artists. Here lives a group of people certain that they are not from this planet.

The road from Albuquerque to Taos runs through Santa Fe, the oldest state capital in the USA. It is New Mexico’s cultural centre, a beautiful city packed with art galleries and studios. Its high altitude, sharp light and mountains have provided artistic inspiration for thousands of painters and sculptors ever since Georgia O’Keeffe, one of America’s most revered painters, moved to the area in 1949. The town is built almost entirely with adobe – desert clay mixed with straw, sticks and water – and the buildings are low-lying, with rounded corners. Adobe is true desert architecture; the buildings look as if they have arisen out of the earth of their own accord, strong and hardy like yucca trees, but with a childlike naivety that makes a stroll around town feel like you’re entering a cartoon world.

An ancient example of adobe architecture exists at Taos Pueblo, a Native American settlement on the edge of Taos, in the north of the state. The Pueblo peoples are one of the oldest groups of Native Americans, and there has been a community living in the multi-tiered adobe buildings in Taos for some 1,000 years. Small, boxy, yet surprisingly spacious rooms are stacked up on each other, with ladders between the levels. When they were first built, the only way into each apartment was through holes in the roofs – the lack of ground-level entry points meant that the Pueblo could draw up the ladders in defence when attacked by groups such as the Spanish conquistadors or rival Native American nations.

Cameron Martinez, or New Eagle to give his Pueblo name, is a 29-year-old film student who grew up in a second-floor ‘apartment’ on the north side building. ‘I feel lucky to have lived somewhere with such a historic link to our ancestors. Unlike other Native nations, we’ve never been relocated – our people have lived in this place for centuries,’ he says. ‘There is no electricity or running water within the Pueblo. Most people have a modern house elsewhere on the reservation, and so the time spent living in the Pueblo is for intense religious rituals, for learning how to live in the traditional ways, to become selfsufficient.’ The Pueblo people are avid hunters and Cameron says that he still uses a handmade bow and arrow to shoot down birds from the sky.

As for so many people in New Mexico, that blindingly blue firmament plays a significant role in Pueblo culture. Indeed, the Pueblo people here believe that they actually come from the skies or, to put it another way, that they are extraterrestrial. ‘Our stories tell us that we originated in the cosmos,’ says Cameron, scanning the 360-degree mountain horizon that wraps around the settlement. ‘We don’t believe we are from this planet; we are forces of energy that came from somewhere else, but took human shape. And when we die, our bodies will return to this Earth, but if we have lived according to the traditional ways, our souls will flow back to the sky as energy’.

Much of the northern swathe of the state belongs to Native peoples – Pueblo, Apache, Navajo. Each nation has its own creation stories, its own legends that help to explain how the environment in which they live came to be, and how they as people arrived in these lands. But for all the differences, there is a common thread – and it’s no surprise that the sky is the overarching link.

Shiprock is a roadside town and administrative centre in the Navajo reservation. It takes its name from the huge, red rock that stands aloof in the desert, towering above a narrow ridge that points towards it like an arrow. In Navajo language, this rock is called Tsé Bit’a’í, the rock with wings. Legends about its origin vary from it being a flying rock that brought the Navajo people to this area, to being the home of two huge bird monsters who occasionally swoop down from the sky and feast upon any Natives they find below.

The tension between the two Navajo legends – on the one hand, the sky being the source of life, on the other, a constant threat – is one that lies at the heart of the alien obsession here: are aliens helpful friends contributing their technological expertise? Are they intruders looking to abduct anyone who crosses their path? Or are tales of their existence a front for the military who want to dominate the skies with explosive force? Whatever the truth, there’s no doubt that travelling through this huge land makes you conscious of how small human beings are in the grand scheme of things. Perhaps it’s no surprise, then, that New Mexico is a place that’s forever looking up to the heavens for something bigger than itself.

The article 'New Mexico’s alien nation' was published in partnership with Lonely Planet Traveller.