One of the most interesting and odd expenditures that I can imagine

is what became China’s ghost towns. The plan was to encourage those who live far away from production areas to move to these cities for continued growth in workers. However, they built them but the people did not come. The cost must have been massive. If you are not familiar with them, check them out.
Can you find any governmental expenditure in another country that seems unusual or just particularly interesting that you would like to share?