The road is about 90 kilometres long, but it has so many bends that driving it slowly takes hours. It climbs to 2,042 metres above sea level - so high that even in midsummer there is snow at the top. For about half the year, between October and June, it is closed because of ice.
From above, the road looks like a tangled grey ribbon dropped onto the mountains. There are over 800 sharp curves and dozens of tunnels and bridges. One section near the top folds back on itself again and again, like a stack of switchbacks.
At the very top of the climb sits a beautiful lake called Bâlea Lake. It is a 'glacial' lake, which means it was scooped out by an enormous slow river of ice during the last ice age, around 10,000 years ago. The water is icy cold even in summer.
The road is so famous that a British TV show called it 'the best road in the world'. People come from all over Europe on motorbikes and bicycles to ride it. Going up the mountain by bike takes most people most of a day - and then you get to whoosh down again.