It is a name out of the past, like Quemoy and Matsu, Berlin and Pan-munjon, a reminder of the 1950s and the Cold War. And here at Guantanamo Bay the old symbols of the Cold War still exist.

A mile away, across an ugly serpentine scar marked by mine fields, tank traps and rolls of concertina barbed wire, a camouflaged watchtower rises above the tan, cactus-studded hills. It is identical to a tower on this side of the fence line.Atop the far lookout a Cuban soldier, a member of the elite Frontier Brigade, keeps a silent watch though huge tripod-mounted field glasses. On this side a U.S. Marine watches the Cuban watching him. It's a game, a deadly serious game, but a game nonetheless.

On this side of the wire live and work 6,500 U.S. sailors, Marines, civilian employees and their families. This U.S. Navy base at Guantanamo Bay, or "Gitmo" as it is called more commonly, is unique in its location, geography, isolation and way of life.

"Gitmo was originally a coaling station. Now it is a training facility," said Capt. John R. Condon, commander of the base. "It's a good warm-water port, enjoys excellent weather and because there is no civilian air or surface encroachment, an excellent training base."

Gitmo is the oldest U.S. military base on foreign soil. Americans first came ashore at Guantanamo Bay June 14, 1898, when a battalion of Marines landed at Fisherman's Point during the Spanish-American War and, fighting alongside Cuban guerrillas, routed a superior force of 8,000 Spanish regulars and bottled up the garrison at Guantanamo City.

Following the war and Cuban independence, a prescient President Theodore Roosevelt whose "big stick" was a big Navy concluded a treaty in 1903 granting the United States a permanent lease on the bay and its surrounding land.

The treaty was renegotiated by President Franklin Roosevelt in 1934 as part of his "Good Neighbor" policy toward Latin America. Under the treaty, the United States retains complete jurisdiction and control over the 45 square miles of land and water inside the 17.5-mile-long fenced perimeter.

The United States recognizes the ultimate sovereignty of Cuba over the leased areas and allows free commercial navigation through the bay. It is not uncommon for Soviet and East-bloc merchant vessels to pass U.S. Navy ships on their way to the upper bay to take on cargoes of sugar and salt at Guantanamo City. That these "civilian" ships gather intelligence on the base's activities is assumed.

Unlike the leases on other U.S. overseas bases, the Guantanamo treaty is open-ended. With no fixed expiration date, the bay would revert back to Cuban control only if it were abandoned, or by mutual consent of Washington and Havana. Neither has occurred, and the United States makes a point of observing scrupulously every article of the agreement.

The feature that makes Gitmo so important to the Navy is the result of geologic accident, the trace of which is visible at the narrow mouth of the

mile-wide bay between Leeward and Windward Points. There a distinct line, looking almost as if it had been incised on the surface of the sea, separates the shallow turquoise waters of Guantanamo Bay from the deep cobalt-blue waters of the Caribbean. The precipitous slope of the Cuban landmass into the ocean depths means that Navy ships can begin deep-water operations literally within minutes of leaving the pier.

"There is no other naval training facility like it in the world. It is irreplaceable," said Capt. Albert Johnson, commander of the Fleet Training Group, the largest of Guantanamo's four major commands and the primary activity of the base.

U.S. Atlantic Fleet ships training out of ports along the eastern seaboard of the United States generally must spend up to six hours steaming time just to stand off the shallow waters of the continental shelf and to be clear of commercial aviation and surface ship traffic. The remoteness of Gitmo and the proximity of deep water means the Navy saves hundreds of hours in training and can conduct intense exercises that simulate combat conditions as realistically as possible. It's also free of air restrictions, permitting anti-air warfare exercises.

Everyday life at Gitmo changed overnight on Jan. 4, 1961, when the Eisenhower administration broke diplomatic relations with Cuba. In response, Castro sealed off the base. Suddenly, the Navy facility had no local economy on which to draw. Hundreds of Cuban civilian workers had to be replaced with Jamaicans, 800 of whom still work on the base.

Despite raising his "Cactus Curtain," Castro permitted a few Cubans who were employed by the Navy prior the revolution to continue working at the base. Each workday they rise at 4 a.m. to ride buses to the only point of entry, the only break in the bristling defenses between the U.S. Navy base and communist Cuba.

On its side of that gate, Castro's government requires the workers to strip, leave their "Cuban" clothes behind in lockers and to don their "American" work clothing. They pass through the Marine checkpoint and catch another bus for the short ride into Gitmo. In the evening they repeat the process in the other direction.

The isolation of the base from the rest of the island created Gitmo's unique environment. Everything from fresh vegetables to jeans must be brought in twice monthly by barge. Less than 10 percent of the base's resupply arrives by air.

Castro took advantage of the base's isolation in 1964 when he shut off the flow of fresh water. The United States responded by dismantling a desalinization-electric generating plant in Point Loma, Calif., shipping it to Gitmo and reassembling it in less than 90 days.

Supply problems and the difficulty of getting off the island there are only two passenger flights a week to Norfolk, Va., for all naval personnel are the problems nearly all Gitmo's residents cite as the biggest drawbacks.

"Most people either love Gitmo or they hate it," Condon said. "Nobody's ambivalent."