Duluth, Minnesota four Catholic schools with coverage up to grades 6 or 8, two Protestant schools, two Montessori schools, and six other charter and private schools. Due to its proximity to the Great Lakes, Duluth is the location for the Large Lakes Observatory. The Large Lakes Observatory operates the largest university-owned research vessel in the Great Lakes, the R/V Blue Heron. Built in 1985 for fishing on the Grand Banks, the Blue Heron was purchased by the University of Minnesota in 1997, sailed from Portland, Maine, up the St. Lawrence Seaway to Duluth, and converted into a limnological research vessel during the
Duluth, Minnesota winter of 1997–98. The Blue Heron is part of the University National Oceanographic Laboratory System, and is available for charter by research scientists on any of the Great Lakes. Local newspapers include the "BusinessNorth" monthly, the "Duluth News Tribune", the "Duluth Budgeteer News," the free newspapers "Transistor", "The Zenith", and "The Reader Weekly". Locally based nationally distributed magazines include "Cabin Life", "Lake Superior Magazine," and "New Moon Magazine". The Duluth area marks the northern endpoint of Interstate Highway 35, which stretches south to Laredo, Texas. U.S. Highways that serve the area are U.S. Highway 53, which stretches from La Crosse,