UPDATED, 6:10 p.m.
Bomb threats against both Cambridge public schools and Harvard University today proved unfounded, Cambridge Police report.
At Harvard, authorities evacuated the Science Center and Sever, Emerson and Thayer Halls, blocked several roads around Harvard Yard and limited access to Harvard Yard after receiving a bomb threat around 12:30 p.m.
At 5:55 p.m., Cambridge Police reported that extensive searches found nothing and that the campus and nearby roads were fully re-opened.
Police similarly found no evidence of actual explosives at any Cambridge public schools, which remained opened throughout the day but with bolstered police presence.