With no trail post in sight, the unmarked dirt lot outside the Nigerian capital seemed an unlikely place to hike -- but fans of the great outdoors in Abuja have long taken matters into their own hands.

"Most of the trails in Abuja are not properly mapped," said Adebayo Babatunde, founder of Naija Adventurers, adding it was a shame "because nature is a beautiful place where we all need to connect back to".

The group and a handful of others have cropped up to provide a service the government has long left untouched, organising hikes in a city where, despite being ringed by verdant hills, public trails are virtually nonexistent.

More than 400 people made Saturday's trip, a short, 1.5-mile (2.5-kilometre) jaunt up the steep, rocky outcrops that jut out of the central Nigerian plains.

"It keeps me fit," said Jeremiah Makpum, a 32-year-old regular, adding that the large group presence helps him feel safe -- not a small thing in a country suffering from regular jihadist violence and violent kidnap-for-ransom gangs.

Naija Adventurers, like the other half-dozen or so hiking groups in Abuja, doesn't reveal the exact location of its hikes until its members have met up to carpool.

An advance team goes out in the days before to scope out the trails, which are not made for hiking but rather used by farmers or livestock herders.

While Saturday's hike was a welcome reprieve from the group's longer, more punishing day trips, it was still augmented by the usual slew of volunteer organisers and medical personnel -- and armed security.

"If anything happens you'll be amazed, the amount of guns that will come out" from plain-clothes volunteers, Esesua Adeyemi, another organiser, told AFP.

- Hiking, Nigeria style -

As the group rounded the first summit, an expanse of farmland and rocky crags -- bright green from the seasonal rains -- opened up.

But if anyone was hoping to quietly commune with nature, that's not how Naija Adventurers rolls.

Hikers carried speakers blasting Afrobeats music, while organisers shouted words of encouragement to the sweaty trekkers. At a rest stop, dance parties and an aerobics class broke out.

Vendors lugged sunglasses, perfumes and drinks, hawking their wares on blankets spread on top of a cliff, as men showing off their abs spread out yoga mats and challenged each other to crunches.

One of the organisers carried a flag emblazoned with the text "Born To Explore".

But the country's rapidly urbanising character means many, especially the urban poor, grow up cut off from the countryside.

"Like the waterfalls, we have dams, we have farms, a lot of tourist attractions in Abuja," said Kingsley Uche, founder of Kay Hikers, a 5,000-member outdoors group. "The problem is the government presence, they're not focused on it."

National parks exist in varying states of repair across the nation, sometimes along dangerous roads. Police in April warned against hiking and camping in the Federal Capital Territory without notifying security agencies.

Most trails in the country are passed along by word of mouth, their locations unmarked, though Adeyemi said organisers are in contact with the tourism and culture ministry about getting hiking areas mapped.

The first time he went hiking, three years ago, Joseph Eze's legs were shaking so hard he slowed down the entire group's descent. Now, the 33-year-old farmer is a member of multiple hiking groups.

"It's exercise, it's healthy for me," he told AFP, while the massive crowds help with making friends.

"It lets you relieve a lot of things in your head."