Main Street, Venice. The main thoroughfare for traffic in Venice, the Grand Canal winds its way in a 2.4 mile S-shape route from the lagoon near the Santa Lucia railway station to the basin near St. Mark's Square. The Grand Canal is 100 to 300 feet wide and has an average depth of 16.5 feet. More than 170 buildings line the Grand Canal, dating from the 13th to the 18th centuries.