ASHINGTON, Aug. 16 — Everywhere you turn on Washington's fashionable Embassy Row, a new palace-size building is under construction, a testament to the frenzied competition of other nations to gain attention in the capital of the last remaining superpower.

More than a dozen countries have built or are in the midst of building embassies the size of castles. They come adorned with faux towers and real waterfalls in what one diplomat called "neo-this and made-up-that architecture."

From these castle-bastions, foreign diplomats conduct what they call the new Washington diplomacy, an explosion of events geared to reaching the broadest possible audience in hopes of being heard above the din of other countries competing for the same elusive prize of influence.

One recent sticky summer evening, the Swedish ambassador welcomed his guests with chilled vodka and what he called the most important news of the year: Sweden had just received permission to build a new embassy here.

"This is the most powerful country in the history of the world, and we need a showpiece for Sweden," said the ambassador, Jan Eliasson.

Then, to underline the seriousness of the venture, the ambassador pointed to a successful Nordic rival, "Like the Finnish Embassy."

In the growing international race to make a statement here, Finland was one of the first to build a new embassy. Its spacious moss-green granite-and-glass showplace, completed in 1994, has become an unlikely social center, luring the reclusive elite of Washington with ever more inventive gatherings.

"I had staffers from the White House and Congress over last March," said Kristiina Helenius, press counselor for the Finnish Embassy. "We took a sauna at the embassy, had dinner and watched the U.S.-Finland hockey game very late into the night. I had no idea a building could be such an important diplomatic tool."

In Washington, where senior politicians pride themselves on working hard and playing little, it has become increasingly difficult to lure members of Congress and top administration officials, no less cabinet members, to dinners and receptions.

"Most people don't bother to go to those big `bun fight' receptions anymore," said the spouse of an administration official. "It has to be really worth it to get us to an embassy."

Even with their new, gleaming edifices, the embassies must come up with ever more exciting events, like last month's invitation from Denmark for cocktails aboard a vintage tall ship docked temporarily in the city's harbor.

To appeal to local tastes, the embassies are also veering away from the traditions of their countries. At the Japanese Embassy's summer barbecue, guests who did not want sushi were plied with burgers and allowed to use the ambassador's private tennis courts.

To heighten its profile, Italy built an immense pale pink palazzo last year on four wood-lined acres in the heart of Embassy Row. To add star quality to its receptions, the embassy has flown in Alessandra Rizza, the soprano, and Carla Fracci, a prima ballerina, to sing and twirl in the embassy's glass-domed auditorium.

"Now if you want a place in the life of this city, you have to do a lot of work in the humanitarian, cultural and social spheres," said Ferdinando Salleo, the Italian ambassador. "To do that you need space, the space of a new, modern embassy."

Singapore held a send-off reception for Miss District of Columbia before she left for the Miss America contest in the name of improving community relations — hardly the classic definition of diplomacy.

"Cultural and social activities let you show who you are to a wide range of people," said Ambassador Chan Heng Chee of Singapore. "This country may be very powerful, but it is also very mobile. You never know one day who is going to be part of the new elite."

The Austrian Embassy knows that well. The embassy once put on a banquet reception and awards ceremony for Search for Common Ground, the nonprofit organization in Washington dedicated to conflict resolution, featuring Dov Zakheim, a little-known defense analyst, who presented an award for sports diplomacy to the Baltimore Orioles and a representative of Cuba.

Months later, Mr. Zakheim became the comptroller at the Pentagon, and Austria had a friend in high places.

For Washingtonians, who once had to cultivate every new ambassador to win patronage for charities, this new involvement by embassies in nonprofit causes has changed the steps of the diplomatic dance.

Gone are the days of endless black-tie diplomatic balls and whispers of dalliances that underpin the narrative of "Heartburn," the divorce classic of Washington high life that was published in the 1980's. Instead, embassies are more likely to embrace causes like the Washington Symphony, donating their large spaces for charities of all kinds.

"Before, embassies held exclusive, glamorous events," said Ina Ginsberg, a journalist and Washington grande dame. "That's almost all gone. Now it's practical, down to earth and open to all because of their involvement in civic charities. Local charities couldn't exist without embassies now."

Many of the new buildings are being constructed in a sort of embassy park set aside by the city. The land is a northwest extension of the current Embassy Row, between the University of the District of Columbia and the Israeli Embassy.

At the State Department, officials diplomatically skirt the issue of whether countries are trying to one-up one another by building bigger and better chanceries. But they acknowledge the construction boom.

Even China, traditionally a thrifty nation when it comes to housing its bureaucrats, has hired I. M. Pei's architectural firm to design a new embassy compound.

"There is no doubt that Washington is seen as the premier diplomatic capital in the world," said the deputy assistant secretary of state, Theodore E. Strickler, who heads the office of foreign missions. "Every country wants to be represented in the best possible way, and that extends beyond sending their best diplomats and staff. It also involves the quality and appearance of their embassies."

Spanking-new embassies can never guarantee the kind of success the British have enjoyed in this city over the decades. Language, snob appeal and latent Anglophilia consistently attracted Washington's great to the ambassador's residence, built like an English country manor.

But at the Queen's Jubilee reception this year, even the British failed to draw many heavyweights from the administration or Congress.

"This is a very serious question," Ambassador Christopher Meyer said. "A foreign embassy needs to create a hub for networking with movers and shakers, and we're fairly successful at that."

Then he admitted that while the residence remains grand, the embassy is starting to look shabby, given the new castles growing around it.

"One of these days, we're going to have to build a new one," he said.