It's a white elephant project but it's a nice engineering feat too 20 billion is too much money.Most Istanbul residents against this project - could potentially harm nature, the underground water, a hole in the Turkish State Budget, while funding companies which are closely related to Erdogan - also, there is a risk in international Geopolitics if US navy enters in the Black Sea.
Is Erdogan's project a subtile way of improving his overall image, thus, forging and establishing in the long run his legacy?
Not good in my opinion.
It's an impulsive decision, an unpopular one !