Today, the inner-most planet of our Solar System is making a transit across the sun.http://www.nasa.gov/feature/goddard/2016/satellites-to-see-mercury-enter-spotlight-on-may-9 The small planet cross the front of the sun (from our viewpoint) a dozen or some times a century, and it really is a thing of beauty.
The seven and a half hour event is being covered extensively on NASA’s website, and can be watched on YouTube.