A boat sails up the Tagus river in Lisbon as the moon rises Friday, Aug. 28 2015. When the moon rises Saturday, it will be the first full moon supermoon of the three that will occur in 2015. Supermoon, or perigee moon, is the name given when the full or new moon comes closest to the Earth making it appear bigger.

A perigee moon, also known as a super moon, rises above the remains of a medieval fortress in the town of Novogrudok, 150 kilometers (93 miles) west of the capital Minsk, Belarus, Saturday, Aug. 29, 2015. The supermoon happens when moon is full and makes it closest approach to Earth in her orbit.