Question: Where does canal du midi start and finish?
Disambiguated questions and answers: question: In what body of water does canal du midi start?
In what body of water does canal du midi finish?
Strictly speaking where does the constructed canal du midi start and finish?
answer: the Garonne
Bassin de Thau
Étang de Thau
the Étang de Thau on the Mediterranean
from Toulouse to the Mediterranean
Natural Questions answer: the city of Toulouse (from the Wikipedia article "Canal du Midi")