get the last N records in mongodb

In order to get last N records you can execute below query:

db.yourcollectionname.find({$query: {}, $orderby: {$natural : -1}}).limit(yournumber)
if you want only one last record:

db.yourcollectionname.findOne({$query: {}, $orderby: {$natural : -1}})

db.collection.find().limit(1).sort({$natural:-1})