Every tourist coming to visit Rome knows what to expect from the Eternal City: museums overflowing with works of art, archaeological monuments of immeasurable historical value, and solemn churches in every corner of the city. Also, for this reason, many define Rome as an “open-air museum”, but just a few of them know that, in addition to the Colosseum and the St. Peter’s Basilica, there are many unknown places, suggestive and curious, able to capture their attention.

Did you know, for example, that in Rome there are many optical illusions that can leave you literally stunned? Of course, not all of them are so famous or easy to visit, and that’s why we have Vincenzo Spina, who works as a Tour Guide and is part of the Rome Guides Association, to suggest you the 5 best optical illusions in Rome: the next time you visit Rome, let him guide you to discover the magical mysteries of the Eternal City.

1  – THE CHURCH OF ST. IGNATIUS OF LOYOLA

The Church is located a few steps from Via del Corso and a few hundred meters from the Pantheon. The solemn façade, which dominates the elegant small square in front of it, hides the mysterious charm of the interior.

This church, indeed, houses two optical illusions, both created by the painter Andrea Pozzo at the end of the 17th Century. The first one, less famous but very spectacular from an artistic point of view, dominates the central nave: the fresco created by Pozzo almost seems to break through the ceiling, extending the vertical dimensions of the church to an excess, making the roof vanish and uncovering the sacred building towards the sky, giving the sensation of an infinite space.

If this majestic illusion amazes you, you’ll only have to walk a few dozen steps towards the altar to admire one of the most incredible optical illusions of Rome: the so-called False Dome by Andrea Pozzo. This is a canvas painted by the artist, who reproduced in perspective (and in a perfect way) the image of a dome that would remedy the lack of the real one, designed but never built. When you will take a picture and will show it later to your friends, claiming that in reality the dome is just an illusion, nobody will believe you!

2  – BORROMINI’S PERSPECTIVE GALLERY

To see this absolute masterpiece of architectural illusionism you have to go and visit Palazzo Spada, a few steps from the noisy square of Campo dei Fiori. Palazzo Spada not only houses the Council of State, the most important Administrative Court in Italy, but also and above all the Spada Gallery, an important private collection of paintings and works of art.

In order to visit the Perspective Gallery you will have to buy a ticket for the Museum, which I recommend you visit first, keeping the magical surprise of the Perspective Gallery at the end of the tour, when you enter the inner courtyard.

The Perspective Gallery was designed by the great baroque architect Francesco Borromini, with the clear intent to amaze the visitors of Palazzo Spada. Here, the illusion consists of a game of spatial depths that make the gallery seem 40 meters long, when in fact it has a length of only 8 meters. The explanation is that the different levels converge on a single and unique vanishing point: as the floor goes up, the ceiling goes down and the walls shrink. The height of the columns, for example, is reduced from about 6 meters to 2 and a half meters, while the width of the gallery narrows progressively, going from three and a half meters at the beginning to only one meter at the end. To accentuate the illusionistic perspective is the statue of Mars, placed at the bottom: it looks huge, but is only 60 centimeters high.

With your best smile, ask the courtyard attendant to remove the rope and walk inside the Perspective Gallery, to use him as a human comparison!

3 – VIA PICCOLOMINI

In the next two optical illusions, the great protagonist will be the Dome of St. Peter.

In Rome, there are actually two magical places where you can observe it in a very unusual way. The first is Via Piccolomini, a few steps from Via Aurelia, where you will find yourself in a world literally upside down: the more you walk in the direction of the dome, in fact, the more it will shrink, while the more you go back, the more it will grow larger and larger.

This is an optical illusion due to the point of observation in which you are located and the arrangement of buildings that stand between your eyes and the Dome of St. Peter. At the beginning of Via Piccolomini, indeed, the human eye sees only one target: the dome, with its solemn dimensions. Walking along the street, the space progressively opens in a different way, showing the background previously hidden by the buildings and modifying the visual perception, instinctively making the dome smaller.

4  – THE MAGIC KEYHOLE

The second place to admire in an unusual way the Dome of St. Peter is located on top of the Aventine Hill, a few steps from the Garden of the Orange Trees.

You’ll have to arrive in the solemn square in front of the Priory of the Knights of the Order of Malta, designed in the 18th Century by Giovan Battista Piranesi. The place you will have to approach will be easily identifiable, as you will probably find a long queue of people waiting to take a picture and bring their eyes closer to the keyhole of a massive door, belonging to the Priory Villa.

This keyhole is so special because it gives a wonderful perspective of the Dome of St. Peter, which appears along the Viale dei Giardini: the view is really exciting, both day and night, and is totally unexpected.

5 – THE ANAMORPHOSIS BY MAIGNAN AND NICERON

The fifth and last optical illusion of Rome is also the most difficult to see, because it is located inside the Convent of the Trinity of the Mountains, at the top of the Spanish Steps: it is open sporadically and not easy to visit, but it is definitely worth it.

The convent is indeed a real treasure chest that holds unexpected wonders: in addition to the refectory, beautifully frescoed in 1694 with illusionistic effects by the already known painter Andrea Pozzo, it also contains two extraordinary wall paintings created in the 17th Century by Emmanuel Maignan and Jean François Nicéron, amazing examples of anamorphosis.

The anamorphosis (from the Greek anamórphosis, “reconstruction of form”) is a technique that renders a figure altered and distorted when observed frontally, but perfectly visible by adjusting the viewpoint with respect to the plane of the image.

The best preserved work dates back to 1642: observed frontally, it depicts a vast and sinuous coastal landscape in which one can distinguish a boat heading towards a small port, while on the shore one can see the figure of St. Francis of Paola. This landscape actually conceals an absolutely incredible optical illusion: looking at the wall transversally, indeed, the landscape is magically transformed into a large St. Francis of Paola in prayer, with the solemn image of the Saint framed by the branches of an olive tree.