Complex sentence: Occupying the full city block between 15th & 16th Streets, and from Eighth to Ninth Avenues, at 111 Eighth Avenue, the building was once Inland Terminal 1 of the Port Authority of New York and New Jersey.
Split into simpler sentences: Occupying the full city block between 15th & 16th Streets, and from Eighth to Ninth Avenues. It is a humongous building that used to be part of the Port Authority of New York and New Jersey.