A woman with her child stands at the bank of the Neva River in St. Petersburg with the St. Isaak Cathedral and the Admiralty in the background. (SERGEY KULIKOV/AFP/GETTY IMAGES)

Two weeks in St. Petersburg, Russia’s planned, pre-revolution capital, kept me thinking about Washington, America’s planned capital.

In many ways, St. Petersburg has become as livable as Washington, thanks to remarkable changes in St. Petersburg since I was last there in 2003. But the changes are especially amazing when recalling the city I first saw 23 years ago, then known as Leningrad.

In 1989, the Soviet Union and its economy were in shambles. Leningrad’s remarkable architecture — more than 3,000 palaces in the historic center — was deteriorating. People lined up in front of mostly empty shops while bedraggled peddlers lined sidewalks and subway stations. Few hotels, restaurants or cafes existed. Many apartments were shared by two or more families. A currency black market thrived. One pack of Marlboro cigarettes would pay for a lengthy ride in an aging, decrepit, unsafe Russian taxi.

Czar Peter I — at 61 / 2 feet tall, known as Peter the Great — would have been dismayed to see how his beautiful planned capital had evolved. He founded St. Petersburg in 1703, 90 years before another Peter, Pierre L’Enfant, was hired by George Washington to plan America’s new capital. Although nearly a century separated their creation, the plans of the Russian and American capitals had much in common. Both abutted rivers and were laid out with avenues radiating diagonally from significant civic buildings or monuments.

The czar sought to create a grand Russian capital, as well as a seaport and navy rivaling European navies, especially England’s and Holland’s. Commerce was also a big consideration. Like George Washington contemplating the Potomac River leading seaward and inland, Peter the Great viewed the Neva River and the Baltic Sea through a business lens. Both expected their new capitals to become major national and international trading centers and busy ports.

The two capitals shared other characteristics. Architects from Italy, Germany and France were invited to St. Petersburg to design ornately gilded edifices. Baroque neoclassicism, in vogue in Europe during the 18th century, was what everyone wanted in St. Petersburg. Neoclassicism was likewise the choice for civic buildings and elegant private homes in Washington during the 19th and early 20th century, although American architects and their clients usually opted for more austere, less opulent compositions.

During the 20th century, war catalyzed Washington’s growth but threatened to destroy St. Petersburg. After World War I, Soviet planning and policies led much of Russia into consumer impoverishment, while capitalism strengthened much of America economically, politically and militarily. Metropolitan Washington prospered; St. Petersburg stagnated.

But after the USSR’s 1991 dissolution, many Russians, especially younger ones, enthusiastically embraced capitalism. This began revitalizing St. Petersburg’s economy and culture. Today St. Petersburg is far from stagnant. Tourism is thriving, private businesses are proliferating and employment is increasing. There are now hundreds of hotels and thousands of restaurants serving every cuisine imaginable, including sushi. American fast-food outlets — Subway, KFC, McDonald’s, Burger King, Baskin-Robbins — are everywhere.

Cafes, stores and boutiques line the city’s avenues, canals, streets and squares, charging surprisingly high prices. Immense, recently developed city-center shopping malls — think Pentagon City and larger — contain every upscale retail chain store on the planet. Fashionably dressed, well-coiffed young women, often in expensive stiletto heels, are as ubiquitous in St. Petersburg as they are in New York or Paris.

Street signs are now in Russian and English, as are menus in many restaurants, and names and signage in Metro stations. The refurbished St. Petersburg subway system is spotlessly clean, bright and well illuminated, with advertising tastefully displayed. Functioning escalators go much deeper than Washington’s. Subway trains with new cars run less than two minutes apart. During subway rides, we couldn’t avoid talking about Washington’s subway system and how unfavorably its current condition compares with St. Petersburg’s.

Like Washington, St. Petersburg adamantly strives to maintain strict height limits in the historic center, designated by UNESCO in 1991 as a World Heritage Site. Thus, the 18th- and 19th-century city fabric remains low, thanks to the efforts of preservationists. But real estate pressures are high. Tall towers have begun sprouting up outside the city center, and skyscrapers have been proposed — and vehemently opposed by local residents — near the center.

Meanwhile, the city is making steady progress restoring, renovating and reusing its palaces and aging commercial structures, in addition to building new buildings. Because urban living has become so desirable as urban amenities have expanded, real estate market demand and prices have greatly escalated, just as Washington real estate values have risen in recent decades. Affordable housing is now available only in St. Petersburg’s suburbs.

The most visible changes, fortunately, have not adversely affected the city’s unique architectural heritage. Yet the sidewalk-level cityscape and pedestrian experience have been transformed. Streets are more visually animated by enhanced storefront graphics and advertising signage — the English word “SALE” appears virtually everywhere — with colorful lighting and display windows filled with merchandise of all types and quality.

Junky Russian cars have disappeared. Instead, St. Petersburg’s streets are congested with Fords, Volvos, VWs, Mercedes, BMWs, Toyotas, Hyundais and Hondas. The city finally has painted wide-striped crosswalks at signalized intersections where, unbelievably, St. Petersburg motorists actually stop for pedestrians. Whenever I crossed a street, I thought of Washington crosswalks that drivers frequently disregard. Also streets are generally litter-free, another surprising contrast with D.C. Because smoking is now prohibited in most public establishments — and fewer Russians smoke — you rarely see a cigarette butt.

This is the new St. Petersburg and, for many of its residents preoccupied with their mobile phones and other consumer products, the new Russia. Few seem to care about or pay attention to Russian politics. They are too busy trying to live the good life in their now very livable city.

Roger K. Lewis is a practicing architect and a professor emeritus of architecture at the University of Maryland.