There was a whole room down there—a modern office, I saw. I glimpsed a desk, a girl behind it in a simple white smock, peering up at us. Fluorescent light glared up gray-white but dazzling bright after the gloom of the Catacomb. I was amazed—even stunned. It was the last thing I’d have expected to see; it was hard to believe it was real.

Rosa was grinning. “Welcome to my underground lair, Austin Powers.”

“Not funny,” I snapped.

“Oh, lighten up.” She turned and descended. I followed.

And so I entered the Crypt for the first time.

The receptionist sat behind her wide marble desk, smiling at us. I glimpsed a winking rack of small TV monitors behind the surface of the desk, and one red-eyed camera peered directly at me from a wall. It was all quite normal, electric bright, certainly not as chill as the Catacombs. But there was no daylight, of course, not a scrap; it reminded me how far I was underground.

“We don’t use this entrance much,” said Rosa. “There are many ways in, from our shops and offices on the surface—most of them in the suburbs to the west of the Appian Way—though we have a couple of routes that lead to the center of the city. But I wanted to bring you this way. It is the oldest.” She smiled, almost mischievously. “I suppose I wanted to put on a show . . . Are you okay?”

I simply had no idea what to expect. “I’ve never been in a convent before,” I said.

“You aren’t in one now. Come on.”

We walked toward the wall of the anteroom. Automatic doors slid out of sight. We stepped into a corridor, just as brightly lit as the anteroom.

The corridor curved out of sight. It was my first impression of the true size of the place. For sure it was a hell of a lot bigger than the anteroom.

And the corridor was full of people: a great murmuring crowd, deep underground.

There must have been hundreds, just in that first glimpse. The human traffic in that corridor was as dense as Oxford Circus on a summer Saturday, or Times Square at New Year. Most of them were women. Many were in street clothes, but some wore a kind of uniform, a simple white dress or trouser suit with sewn-in threads of purple. They walked in neat files, passing in and out of the rooms that branched off the corridor.

Then there was the smell: not an unpleasant smell, not a locker-room stink, but there was something animal in the air, something potent. The air was hot, humid, and noisy; I found myself breathing hard, dragging for breath.

All this concealed far underground, under that sleepy tourist-trap park.

Nobody seemed aware of anything strange, nobody but me. It was all I could do to keep from staggering back, into the relative calm of the anteroom.