Just west of Rome’s modern Termini train station, this area offers an extraordinary Roman blend of old and new. Although ancient artworks, great Bernini sculptures, and baroque landmarks lure the traveler, this was, for the most part, the “new” Rome of the 19th century—the area owes its broad avenues and dignified palazzi to the city’s transformation after 1870, when it became the capital of a newly unified Italy.

Toward Via Veneto, the influx of ministries set off a frenzied building boom and distinguished turn-of-the-20th-century architecture became the neighborhood’s hallmark. As a gateway, Piazza della Repubblica was laid out to serve as a monumental foyer between the rail station and the rest of the city. And as this square proves, time in Rome comes layered like nowhere else on earth.

Flanking the train station’s plate-glass entrance is an elephantine-colored mass of masonry that dates back millennia—a stretch, no less, of the so-called Servian Walls, the city boundary built when Rome was still a Republic way back in the 6th century BC. Fast forward about three centuries to find the piazza’s main landmark: the vast ruin of the Baths of Diocletian—the Terme di Diocleziano—which were subsequently transformed into a Renaissance monastery and, designed by Michelangelo himself, the church of Santa Maria degli Angeli. Following the layout of the ancient baths and the concave entrance to the church (with the nearby 1890s buildings curving likewise as if in tribute), the piazza is a square only in name. At its center lies the turn-of-the-20th-century Fountain of the Naiads, which works wonders with the Roman sunlight. Its busty nymphs and buffed sea tritons announce that beauty awaits at many of the sights in this district.

Off right or west from Via Nazionale lies the Quirinale, a hill set with various jewels of the baroque era, including masterpieces by Bernini and Borromini. Nearby is Palazzo Barberini, a grand and gorgeous 16th-century palace holding five centuries of masterworks. For ancient art treasures, head for Palazzo Massimo, famed for the fabulously frescoed rooms of the Empress Livia’s summer villa, colorful and vibrant with birds.

Mercifully situated away from traffic is the lofty Quirinale hill, set with various jewels of the baroque era. Crowning the piazza is the enormous Palazzo del Quirinale, built in the 16th century as a summer residence for the popes. It became the presidential palace in 1946—you can tour its reception rooms, which are as splendid as you might imagine. The changing of the guard (daily at 4), outside on the piazza with its oversize stairway, is an old-fashioned exercise in pomp and circumstance.

While Bernini’s work feels omnipresent in much of the city center, the Renaissance-man range of his work is particularly notable here. The artist as architect considered the church of Sant’Andrea al Quirinale one of his best; Bernini the urban designer and waterworker is responsible for the muscle-bound sea gods who wrestle so provocatively in the fountain at the center of whirling Piazza Barberini. And Bernini the master gives religious passion a joltingly corporeal treatment in what is perhaps his greatest work, the Ecstasy of St. Theresa, in the church of Santa Maria della Vittoria. Along with Bernini, this area has big boulevards, big buildings, and big delights.