Read here about 10 projects that have gone wrong.
These projects all had massive budget over-runs, some running into billions of dollars.
Some projects were poorly conceived - the wrong project, in the wrong place, at the wrong time. The became 'white-elephants'. Some were built to satisfy personal egos. Some were political decisions.
Many projects were not bid properly, were affected by corruption or were not managed properly.
Despite these and numerous other examples there is a continuing legacy of disastrous projects.