The City Council shall have the power to open or widen any street, alley or lane within the limits of the city; and also to create, open and improve any new street, alley or lane; provided, all damages sustained shall be ascertained in such manner as shall be provided by law. Streets and alleys may be vacated as and when the Mayor and City Council deem it necessary for the public safety, welfare and convenience and the title to the land so vacated for street or alley purposes shall revert to the owner or owners of the lot or lots from which it was originally taken, as provided by law, one-half on each side thereof.