“The tunnels were created in Roman times, when limestone was excavated from underground,” Sébastien said. “In 1786, Parisian cemeteries were overcrowded, and the areas surrounding them had become unhealthy. It was decided to move the bones of those buried in the cemeteries to these tunnels. You are about to view the remains of seven million Parisians.”

Even with those ominous words, Amy wasn’t prepared for what she was about to see. They entered a gallery lined with the remnants of various body parts of former human beings. A collective gasp erupted from the group as they faced walls made up of bones and skulls.

They moved slowly. Amy could hear the wet gravel beneath her feet. And no one spoke—as if it would be rude to disturb the dead. Amy couldn’t remember ever seeing anything so eerie before in her life. In some galleries, the bones were just piled in heaps. But in other galleries, the piles were very orderly, with bones of a particular body part lined up side by side, then topped with bones from another part. They formed patterns, these bones, like intricate weavings, topped with skulls for decoration.

As she looked at these masses of bones, particularly the skulls, Amy tried to envision them as people, but it was impossible. Still, they had all been flesh and blood once. Each skull represented a human being with a face and a personality, with unique features and feelings. But to look at them now, you couldn’t know which were men and which were women … who was young, who was old … who was fat or thin, pretty or ugly. Down here, everyone was equal.

Dimly Amy became aware of the sound of dripping water from above. She looked up and saw stalactites hanging from the ceiling. It made the whole experience of the Catacombs seem otherworldly.

She didn’t know how Annie could call this one of her favorite places in Paris, and she was grateful when Sébastien began speaking again.

“What you are seeing is only a small portion of the Catacombs,” he said. “Miles of tunnels exist under Paris, but the public is not allowed to visit them. It would be too complicated to keep track of everyone. To make sure no one got lost. So the police have sealed the entrances.”

Amy had been eager to visit the Catacombs, but now that she was here, she didn’t know who would want to sneak into this labyrinth of tunnels on their own.

Sébastien continued. “During World War Two, the German occupation forces had a communications center in the Catacombs. Interestingly, the French Resistance, the group which actively fought the Nazis, also made use of the Catacombs and held their secret meetings here. Yet there is no evidence that the two opposing groups ever encountered each other. This demonstrates how vast and tangled the underground network is.”

Amy found this historic fact fascinating. Having good guys and bad guys roaming these tunnels, hiding from each other, seemed very dramatic, even a little romantic. Now she looked around with more interest and less fear.

Even so, she was glad when the tour ended and they went back up to the surface. The gray sky was like brilliant sunshine after the gloom below.

“Did you enjoy that?” Annie asked her.

Amy didn’t want to let on how she’d felt underground. She didn’t want Annie to think she frightened easily. That would be so—un-clone-like. “Oh, it was great,” she said. “Really great.”

The girls ate a late lunch, during which Amy was introduced to the popular French sandwich the croquemonsieur. It was like a grilled ham and cheese, and it was totally delicious. By the time they finished, Annie said they had to get moving if they were going to meet Monica and Christophe on time.

“At this moment, we are in the south of Paris,” she told Amy. “Montmartre is at the farthest northern point.”

But it didn’t take them long to get from one end of Paris to the other on the speedy Métro. They even reached Montmartre early, which allowed them to climb what seemed like hundreds of steps to get a spectacular view of Paris. The climb down was much faster, and soon they were in a square, surrounded by little shops and cafés. Artists had set up easels and were offering to paint portraits of the tourists.

They reached the designated corner at precisely the same time that Monica and Christophe arrived. “What did you girls do today?” Monica asked them.

When Amy reached the part about the Catacombs, Christophe smirked. “But you took the guided tour. You did not see the real Catacombs.”

“The guide told us the public isn’t allowed in the other tunnels,” Amy replied. “He said the entrances are all sealed.”

“Some entrances are sealed,” Christophe acknowledged. “But if one knows where to go, one can get into the forbidden Catacombs.”

“Why would you want to go in them?” Amy asked. She looked at Annie, who was listening to Christophe with obvious interest.

“Have you been in the forbidden Catacombs?” Annie asked him

“I have not toured the entire network,” he said. “But there is an area where I go quite frequently to meet fellow artists.”

Incredulous, Amy asked, “You paint down there?”

“Not exactly,” Christophe said. “It is a place for social gatherings.”

Amy was dubious. The Catacombs didn’t look like Party Central to her.

At that moment, a church bell struck four. “I must go now,” Annie said. “There is a performance tonight.”

“A performance?” Monica asked. “Of what?”

“Annie is in the ballet company we saw last night,” Amy told her. “Isn’t that a wild coincidence?”

Fortunately, Monica was the kind of person who believed in coincidences. “You girls were fated to meet!”

“Can we get together tomorrow?” Amy asked Annie.

Annie nodded. “You could meet me after school, if you like.”

“Great,” Amy said. “Just tell me when and where.”

Annie took a pad of paper out of her bag and wrote on it. “This is the address of my school,” she said. “Can you be there at four-thirty?”

“Absolutely.” They embraced and did the cheek-kissing thing again. Then Annie ran off toward the Métro.

“She seems like a very nice girl,” Monica said.

“She’s a lot of fun,” Amy agreed. She looked at the paper Annie had given her. Her eyes widened.

Above the address were written the words Lycée Internationale.

The same words she’d seen stamped on Andy’s notebook.