Michael Bloomberg, the former mayor of New York and one of the world's richest people, is donating $1.8 billion to his alma mater, Johns Hopkins University, in an effort to boost financial aid for low- and middle-income students. The university said the contribution — the largest ever to any education institution in the U.S. — will allow Johns Hopkins to eliminate student loans in financial aid packages starting next fall. The university will instead offer scholarships that don't have to be repaid.