The University of Southern Maine has received a collection of nearly half a million maps — an estimated $100 million gift that is believed to be the largest in the history of the University of Maine System.

The collection of more than 450,000 rare maps comes from Dr. Harold Osher, a cardiologist from Portland. The Osher family has previously donated many maps to the university and helped establish the Osher Map Library in 1994.

Family spokesperson Glenn Parkinson said the Oshers hope the collection is used to enhance educational opportunities for local students.

U.S. Senate candidate Zak Ringelstein was arrested outside of a U.S. Border Patrol facility in McAllen, Texas Friday, after blocking access to a detention facility.

According to Ringelstein, the facility was holding immigrant children separated from their parents.

Ringelstein's campaign promoted his visit to Texas on social media, which said he would travel there to deliver blankets, food and toys to children detained at the border and to request access to a holding facility in the city of McAllen.

Maine officials are warning residents to be very careful before removing the cocoons of the browntail moth, a toxic, invasive species that is spreading throughout the state.

“Do this with extreme caution,” a media release issued Thursday from the Maine Department of Agriculture, Conservation and Forestry, said of cocoon removal. “Cocoons are full of the hairs that can cause a rash or worse.”

U.S. Customs and Border Protection agents set up a checkpoint Wednesday on Interstate 95, stopping drivers and asking them questions about their citizenship before letting them proceed.