7 Best Sights in Piazza di Spagna, Rome

This pristine monument sits inside one of Rome's contemporary architectural landmarks: a gleaming, rectangular, glass-and-travertine structure designed by American architect Richard Meier. It overlooks the Tiber on one side and the ruins of the marble-clad Mausoleo di Augusto (Mausoleum of Augustus) on the other and is a serene, luminous oasis right in the center of Rome.

This altar itself dates from 13 BC and was commissioned to celebrate the Pax Romana, the era of peace ushered in by Augustus's military victories. When viewing it, keep in mind that the spectacular reliefs would have been painted in vibrant colors, now long gone. The reliefs on the short sides portray myths associated with Rome's founding and glory; those on the long sides display a procession of the imperial family. Although half of his body is missing, Augustus is identifiable as the first full figure at the procession's head on the south-side frieze; academics still argue over exact identifications of most of the figures. Be sure to check out the small downstairs museum, which hosts rotating exhibits on Italian culture, with themes ranging from design to film.

Like the Palazzo Colonna and the Galleria Borghese, this dazzling 15th-century palace provides a fantastic glimpse of aristocratic Rome. It passed through several hands before becoming the property of the Pamphilj family, who married into the famous seafaring Doria family of Genoa in the 18th century. The family still lives in part of the palace.

The understated beauty of the graceful facade, designed by Gabriele Valvassori in 1730 and best admired from the opposite side of the street, barely hints at the interior's opulent halls and gilded galleries, which are filled with Old Master works. The 550 paintings here include three by Caravaggio: St. John the Baptist, Mary Magdalene, and the breathtaking Rest on the Flight to Egypt. Off the eye-popping Galleria degli Specchi (Gallery of Mirrors)—a smaller version of the one at Versailles—are the famous Velázquez Pope Innocent X, considered by some historians to be the greatest portrait ever painted, and the Bernini bust of the same Pamphilj pope.

A delightful audio guide is included in the ticket price and is narrated by the current heir, Prince Jonathan Doria Pamphilj, who divulges intimate family history. Plan to stay for lunch, or at least pause for a coffee, at the fashionable Caffè Doria, with elegant tables set out in the palace's peaceful cloisters.

Rome's second Jesuit church, this 17th-century landmark set on a Rococo piazza harbors some of the city's most magnificent trompe l'oeils. To get the full effect of the illusionistic ceiling by priest-artist Andrea Pozzo, stand on the small yellow disk set into the floor of the nave. The heavenly vision that seems to extend upward almost indefinitely represents the Allegory of the Missionary Work of the Jesuits. It's part of Pozzo's cycle of works in this church exalting the early history of the Jesuit order, whose founder was the reformer Ignatius of Loyola. The saint soars heavenward, supported by a cast of thousands, creating a jaw-dropping effect that was fully intended to rival that of the glorious ceiling by Baciccia in the nearby mother church of Il Gesù. Be sure to have coins handy for the machine that switches on the lights so you can marvel at the false dome, which is actually a flat canvas—a trompe l'oeil trick Pozzo used when the architectural budget drained dry.

Scattered around the nave are several awe-inspiring altars; their soaring columns, gold-on-gold decoration, and gilded statues are pure splendor. Splendid, too, are the occasional sacred music concerts performed by choirs from all over the world. Look for posters by the main doors, or check the website for more information.

The iconic Spanish Steps (often called simply la scalinata, or "the staircase," by Italians) and the Piazza di Spagna from which they ascend both get their names from the Spanish Embassy to the Vatican on the piazza—even though the staircase was built with French funds by an Italian in 1723. In honor of a diplomatic visit by the King of Spain, the hillside was transformed by architect Francesco de Sanctis with a spectacular piece of urban planning to link the church of Trinità dei Monti at the top with the Via Condotti below.

In an allusion to the church, the staircase is divided by three landings (beautifully lined with potted azaleas from mid-April to mid-May). Bookending the bottom of the steps are beloved holdovers from the 18th century, when the area was known as the "English Ghetto": to the right, the Keats-Shelley House and to the left, Babington's Tea Rooms—both beautifully redolent of the era of the Grand Tour.

For weary sightseers who find the 135 steps too daunting, there is an elevator at Vicolo del Bottino 8, next to the Metro entrance. (Those with mobility problems should be aware that there is still a small flight of stairs after, however, and that the elevator is sporadically closed for repair.) At the bottom of the steps, Pietro Bernini's splendid 17th-century Barcaccia Fountain still spouts drinking water from the ancient aqueduct known as the Acqua Vergine.

Alive with rushing waters commanded by an imperious sculpture of Oceanus, the Fontana di Trevi has been all about theatrical effects from the start; it is an aquatic marvel in a city filled with them. The fountain's unique drama is largely due to its location: its vast basin is squeezed into the tight confluence of three little streets (the tre vie, which may give the fountain its name), with cascades emerging as if from the wall of Palazzo Poli.

The dream of a fountain emerging full force from a palace was first envisioned by Bernini and Pietro da Cortona from Pope Urban VIII's plan to rebuild an older fountain, which had earlier marked the end point of the Acqua Vergine, an aqueduct created in 18 BC by Agrippa. Three popes later, under Pope Clement XIII, Nicola Salvi finally broke ground with his winning design. Unfortunately, Salvi did not live to see his masterpiece of sculpted seashells, roaring sea beasts, and diva-like mermaids completed; he caught a cold and died while working in the culverts of the aqueduct 11 years before the fountain was finished in 1762.

Everyone knows the famous legend that if you throw a coin into the Trevi Fountain you will ensure a return trip to the Eternal City, but not everyone knows how to do it the right way. You must toss a coin with your right hand over your left shoulder, with your back to the fountain. One coin means you'll return to Rome; two, you'll return and fall in love; three, you'll return, find love, and marry. The fountain grosses some €1,500,000 a year, with every cent going to the Catholic charity Caritas, which is why Fendi was willing to fully fund the Trevi's recent restoration.

Tucked away in a little nearby alley is the Vicus Caprarius ( Vicolo del Puttarello, 25), a small museum where visitors can pay €8 for a guided tour that descends into a subterranean area that gives a glimpse at the water source that keeps the fountain running.

The huge white mass known as the "Vittoriano" is an inescapable landmark that has been likened to a giant wedding cake or an immense typewriter. Present-day Romans joke that you can only avoid looking at it if you are standing on it, but at the beginning of the 20th century, it was the source of great civic pride. Built to honor the unification of Italy and the nation's first king, Victor Emmanuel II, it also shelters the eternal flame at the tomb of Italy's Unknown Soldier, killed during World War I. Alas, to create this elaborate marble behemoth and the vast surrounding piazza, its architects blithely destroyed many ancient and medieval buildings and altered the slope of the Campidoglio (Capitoline Hill), which abuts it.

The underwhelming exhibit inside the building tells the history of the country's unification. The Vittoriano has a rooftop terrace, however, that offers some of the best panoramic views of Rome.

Rome's grandest private palace is a fusion of 17th- and 18th-century buildings that have been occupied by the Colonna family for more than 20 generations. The immense residence faces Piazza dei Santi Apostoli on one side and the Quirinale (Quirinal Hill) on the other—with a little bridge over Via della Pilotta linking to gardens on the hill—and contains an art gallery that's open to the public on Saturday morning or by guided tour on Friday morning.

The gallery is itself a setting of aristocratic grandeur; you might recognize the Sala Grande as the site where Audrey Hepburn meets the press in Roman Holiday. An ancient red marble colonna (column), which is the family's emblem, looms at one end, but the most spectacular feature is the ceiling fresco of the Battle of Lepanto painted by Giovanni Coli and Filippo Gherardi beginning in 1675. Adding to the opulence are works by Poussin, Tintoretto, and Veronese, as well as portraits of illustrious members of the family, such as Vittoria Colonna, Michelangelo's muse and longtime friend.

It's worth paying an extra fee to take the guided, English-language gallery tour, which will help you navigate through the array of madonnas, saints, goddesses, popes, and cardinals to see Annibale Carracci's lonely Beaneater, spoon at the ready and front teeth missing. The gallery also has a caffè with a pleasant terrace.