A day stop over in Doha

Many people naturally fly through Doha as its the perfect connection point between Europe and the Asia Pacific, but its a shame that so few people actually leave the airport because Doha is a very decent one day stop over option.  It’s small enough and quiet enough for you to get around quite easily, in particular to and from the airport, and has 4 activities that are super close together and so very doable in a day