Chinguetti is a city in Saharan Mauritania.
Cars run from Atar at least once per day.
IMPORTANT: Chinguetti has no facilities of any kind other than Auberges and very basic shops. There are no banks, no places to change money, no restaurants or even cafes, so make sure you take enough money with you from Atar and stay somewhere that will prepare food for you. Cigarettes are only available in a small number of the shops which keep irregular hours and are more expensive than Atar so bring some with you.
The town can easily be walked as it is very small.
Other than the desert of course, the only "landmarks" withing Chinguetti are the mosque and the Islamic library, which are both interesting. However do not expect to find much in the town itself, basically go there in the morning, look round the town in the afternoon, go on your desert tour or whatever the next day and head back to Atar.
Chinguetti has some of the more postcard perfect sand dunes in the Sahara. You can hire a camel and guide to walk you and your things around the desert, but you won't be actually riding the camel. You can also hire a 4-wheel drive. a better option might be to just go on a hike on your own.
The above information is inaccurate, you can take a camel tour where you ride the camel and even camp out for a night or two in the desert if you wish. This can be arranged in Atar or by English-speaking Abdou in Chinguetti at the Auberge Zahar.
There are plenty of auberges, with beds for as low as 1500 ouguiya. You can also easily walk 5 minutes out of town and camp in the desert.
My recommendation would be to stay at the Auberge Zahar. It is 2500 per night, however it is run by a man called Abdou who speaks better English than any other Mauritanian I met in the region. This makes him excellent for arranging camel or four by four tours or cars for you, he is relatively fair with prices. He is also a good cook, which is handy because Chinguetti has no restaurants.