Atar is a city in Saharan Mauritania.
Atar is a small town which is great for exploring the Adrar region and tends to be slightly cheaper overall than Chinguetti. Atar is growing in importance due to its proximity to an airport and a regional hospital.
Atar has an airport which used to be served by a daily flight from Marseille, France but as of writing there are only small charter flights available due to the kidnappings in other parts of Mauritania.
The Iron Ore Train typically departs from Nouadhibou sometime between 2:30 pm and 10 pm, depending when the cargo is finished loading. The most common case is that it leaves sometime between 16.00 and 17.00. There is only one train a day with passenger cars and tickets can be arranged in advance or bought at the Nouadhibou train station (Gare Voyageurs) for around 2500 ouiguiyas. Travel in the bucket cars is free, just climb aboard, but be forewarned it will be cold and dusty. If you decide to travel in an empty cargo car pick the one that doesn't have any "black sand" (small grains of iron ore) as it will really hurt your breathing system once the train starts moving. Be sure that the locals traveling on the train are cool and friendly and don't hesitate to accept their offer to travel with them in the same car. It will enhance your experience in a very positive way. The train stops at Choum in the early hours of the morning where you can easily grab a ride to Atar in one of the many bush taxis or pickups which will meet the train for around 1500-2000 ouiguiyas. Alternatively you can crash in one of a few "restaurants" in Choum for free or for a very small fee and take a ride to Atar in the morning (transport usually comes around noon)
There is a paved and fast road which runs from Nouakchott to Atar served by a variety of minibuses (including one run by a kindly French ex-pat) and bush taxis. All of the rides going to Atar tend to leave [Nouakchott] from the Garage Atar at the end of town. Typical fare is around 4000 ouiguiyas. (500 ouiguiyas, Nov 2018)
Atar is quite small and can easily be walked, although some auberges and resorts lie quite far out of town. Taxis are available and can usually be caught around the traffic circle in the center of town, fares run from around 100-300 ouiguiyas depending on distance.
Atar has a few markets which may be of interest to the souvenir hunter and prices tend to be lower than [Chinguetti] although bargaining is of course expected.
Many of the oases and other natural sites in the region can be seen in day trips leaving from Atar. Ask around at your hotel/auberge to arrange bush taxis, 4x4's, or rent bikes. If your feeling adventurous wander into the market and you will doubtless get offers of obliging drivers ready to show yoy what they consider to be the most interesting sites.
The occasional beer can be found at Auberge Bab Sahara
For its size Atar contains a good number of auberges, hotels and resorts.