What structure, at a cost of more than $110 billion, is said to be the most expensive single object ever built?

The structure which is said to be the most expensive single object ever built is the International Space Station.
Its price is estimated at 150 billion dollars, and it is arguably the most expensive man-made object ever. Many countries have donated money for this station to be created, so it is not a product of one nation only. It is located in Earth's low atmosphere and can be seen with the naked eye from some locations on Earth.