The Vatican City boasts countless great museums, with extensive art collections attracting thousands of visitors everyday. Inside the Vatican Museums a vast number of art pieces and amazing architectures can be admired, belonging to different periods, cultures and countries from all over the world. One of the biggest exhibition spaces inside the Vatican is the Pio-Clementine Museum, built in the 18th century as ordered by Pope Julius II to host countless Ancient Greek and Roman collections belonging to the Papacy. The Niccoline Chapel is a chapel in the Apostolic Palace in Vatican City. It is especially notable for its fresco paintings by Fra Angelico and his assistants, who may have executed much of the actual work. The name is derived from its patron, Pope Nicholas V, who had it built for use as his private chapel. The walls were decorated by Fra Angelico with images of two of the earliest Christian martyrs.