© Getty Images

St. Peter's Square - St. Peter's Square and the city of Rome viewed from the dome of St. Peter's Basilica.

© iStock

The Vatican Museums -

The Vatican Museums boast one of the world's greatest art collections. Founded by Pope Julius II in the early 16th century and enlarged by successive pontiffs, exhibits include classical statuary and masterpieces of Renaissance art.

© Shutterstock

The Vatican Library -

Open to bona fide academics and researchers, the Vatican Library is one of the oldest libraries in the world. The Vatican Secret Archives were housed here until the early 17th century. Pictured is the library's fabulous Sistine Hall.

© Shutterstock

Sistine Chapel -

An undoubted museum highlight is the Michelangelo-painted Sistine Chapel.

© Shutterstock 

'The Creation of Adam' -

Michelangelo's stunning frescoes decorate the chapel's interior. The ceiling is especially decorative and includes the iconic 'The Creation of Adam' panel (pictured). The other great fresco is 'The Last Judgement,' which illustrates the entire altar wall.

© Getty Images 

Pietà -

A world-famous work of art, Michelangelo's sculpture Pietá ('The Pity') is housed in St. Peter's Basilica.

© Getty Images 

An elephant under the Vatican? - An elephant skeleton was discovered under the Vatican's Belvedere Courtyard in 1962. The jumbo pet, named Hanno, belonged to Pope Leo X, who was elected pope in 1513. After the beast died, the pontiff had him buried within the Vatican grounds—where his bones still lay today. Pictured is a sketch made by Raphael of the celebrated animal.

© Public Domain

Gallery of Maps -

An essential part of the Vatican Museums' experience is admiring the 16th-century topographical maps of Italy painted on the walls as large-scale frescoes.

© Getty Images 

Gallery of Maps - Commissioned by Pope Gregory XIII in 1580, it took friar and geographer Ignazio Danti three years to complete the 40 panels.

© Public Domain

Stufetta del cardinal Bibbiena - A tiny bathing chamber in the Vatican's papal apartments is notorious for its frescoes, painted by Raphael in 1516. The secret room is normally off limits to the public.

© Public Domain

Vatican Necropolis -

Set underneath St. Peter's Basilica is the Vatican Necropolis, parts of which date back to Roman times.

© Getty Images 

Vatican Necropolis - The necropolis was originally a burial ground built on the southern slope of the Vatican Hill. Archaeological excavations in the '40s revealed ancient mosaic artwork.

© Public Domain

Tomb of St. Peter -

The necropolis is believed to house the tomb of the Apostle Peter. Guided tours of the site conclude at the supposed burial place.

© Getty Images 

Passetto di Borgo -

An elevated passage that links the Vatican City with the Castel Sant'Angelo, this was once the Pope's secret escape route.

© Getty Images 

Passetto di Borgo -

Centuries old, the passage was used by Pope Clement VII during the plunder of Rome in 1527. It now greets visitors for a limited period each summer.

© Shutterstock

Castel Sant'Angelo - Originally built as a mausoleum to hold the ashes of the Roman emperor Hadrian, the Castle of the Holy Angel was later used by popes as a fortified residence and a prison. It's now a fascinating museum.

© iStock

Original Bramante staircase 1505 -

There are two Bramante staircases in the Vatican Museums. This is the original, dating back to 1505 and found in the Pio-Clementino Museum.

© Shutterstock

Bramante staircase - In the same museum is the modern equivalent. Built in 1932, the impressive double helix design draws inspiration from its 16th-century counterpart.

© iStock

St. Peter's Basilica - The largest church in the world is also a celebrated Roman landmark, a sumptuous example of Renaissance architecture and one of Catholicism's holiest shrines.

© iStock

St. Peter's Basilica -

Dating back to 1626, its principal architects were Donato Bramante, Michelangelo, Gian Lorenzo Bernini, and Carlo Maderno.

© Shutterstock

St. Peter's Basilica -

The Basilica and Ponte Sant'Angelo, seen from the River Tiber.

© Shutterstock

The Raphael Rooms -

Adorned with subliminal frescoes painted by the hand of the great master of the High Renaissance, the rooms constitute the public area of the papal apartments. The phenomenal fresco pictured is 'The School of Athens.'

© Shutterstock

Gallery of Tapestries -

The Ponder the extraordinary tapestries lining this 75-m (246-ft) gallery. Each took years to make and were woven in Rome and Brussels using wool, silk, and gold and silver thread.

© Shutterstock

The Vatican obelisk -

The Vatican obelisk, a needle-like monument brought to Rome from Egypt by Caligula in 37 AD, originally stood near the present-day sacristy. It was moved to St. Peter's Square in the late 16th century.

© Shutterstock

The Apostolic Palace -

The Pope's official residence, this complex hosts the papal apartments along with world-class visitor attractions including The Vatican Museums, Raphael Rooms, and the Sistine Chapel.

© Shutterstock

Pontifical Swiss Guard - The colorful candy-striped uniform of the Vatican's official military guard is wonderfully Renaissance in appearance. But don't be fooled. The force is highly trained in unarmed combat and small arms use.

© Getty Images

Pinacoteca Vaticana -

This Vatican Museum is a veritable palace crammed with priceless art. Head-turning masterpieces include Caravaggio's 'The Entombment of Christ.' But look too for Olivuccio di Ciccarello's 'Opere di Misericordia,' Raphael's 'Transfiguration' (pictured), and Leonardo da Vinci's 'St. Jerome in the Wilderness.' Stunning!

© Getty Images 

Vatican gardens -

Peaceful and verdant, the gardens offer tranquil respite from the overwhelming impact the Vatican's cultural riches often have on the senses.

© Shutterstock

Governor's Palace -

Located in the gardens behind St. Peter's Basilica is the grandiose Governor's Palace, the seat of the Pontifical Commission for Vatican City State.

© Shutterstock

Aventine keyhole -

Standing on Aventine Hill is the Priory of the Knights of Malta. From a keyhole in one of its doors you can peer into the gardens and the perfectly framed dome of St. Peter's Basilica—easily the quirkiest view of Vatican City and a novel way to end your sightseeing experience.

See also: Curiosities about the Louvre and the celebs who have visited it

© iStock