The SEA mobile looked as if it had been assembled from spare parts cast off from a deep submergence lab. The crystal ball cockpit was fifty-four inches in diameter and it was perched on two flotation cylinders the size of water mains. Two protective metal frames shaped like the letter D flanked the sphere.

The vehicle was built to maintain positive buoyancy at all times and the tendency to float to the surface was countered by a midship-mounted vertical thruster. Because the SEA mobile was balanced to remain level constantly, at the surface or under it, the pilot didn't have to fiddle around with pitch controls to keep it at a horizontal attitude.

Using a navigational acoustic Doppler instrument to keep track of their position, Austin guided the vehicle along the underwater escarpment, a broad shelf that gradually sloped down into the deeper water. Following a basic search pattern, Austin ran a series of parallel lines like someone mowing a lawn. The sub's four halogen lights illuminated the bottom, whose contours had been shaped by the advance and retreat of glaciers.

The sub tracked back and forth for two hours and Austin's eyes were starting to glaze from staring at the monotonous gray seascape. Skye was still entranced by the uniqueness of her surroundings. She leaned forward, chin on her hands, studying every square foot of lake bottom. In time, her persistence paid off.

“There!” She jabbed the air with her forefinger.

Austin slowed the vehicle to a crawl and squinted at a vague shape just beyond the range of the lights, then moved the submersible in for a closer look. The object lying on its side was a massive stone slab about twelve feet long and half as wide. The chisel marks visible along its edges suggested that it was not a natural rock formation.

Other monoliths could be seen nearby, some standing upright; others topped with similar slabs like the Greek letter.

“Seems we took a wrong turn and ended up at Stonehenge,” Austin said.

“They're burial monuments,” Skye said. “The arches mark the way to a tomb for funeral processions.”

Austin increased the power to the thrusters and the vehicle glided over six identical archways spaced thirty feet or so apart. Then the ground on either side of the archways began to rise, creating a shallow valley. The natural hillsides morphed into high cyclopean walls constructed with massive hand-hewn blocks.

The narrow canyon ended abruptly in a sheer vertical wall. Cut into the wall was a rectangular opening that looked like the door on an elephant house. A lintel about thirty feet wide topped the door opening and above the huge slab was a smaller, triangular hole.

“Incredible,” Skye said in hushed tones. "It's a tho los

“You've seen this before?” ~~

“It's a beehive tomb. There's one in Mycenae called the ”Treasury of Atreus

“Mycenae. That's Greek.”