The floor and walls were of rough-hewn stone, damp with moisture. Ahead of Sofia, the tunnel sloped gently downward, stretching away into blackness. She moved slowly forward, and as she walked the draught grew stronger. She had been walking for a few minutes when a particularly strong gust of air blew the candle out. Sofia passed her hand in front of her face and saw nothing; the darkness was absolute.
Panic rose up inside her and she had to force herself to breathe. The passage was straight; she could not get lost. All she had to do was turn and follow the wall, and it would lead her back to the dungeon. But first, she needed to find out where this tunnel led. For if it did indeed lead out of the city, then the Turks could just as easily use it to enter. Sofia took a deep breath and reached out to touch the wall. The stones were cold and slimy. She stepped forward, running her hand along the wall as she continued down the passage.
Eventually, the passage stopped descending and levelled out. Shortly after that, the wall she had been following disappeared from under her hand. She reached in front of her but felt nothing, only empty space. She moved back and found the corner where the wall turned sharply to the right. She turned and followed the wall, running her hand along the cold stones. The wall had begun to curve away from her to the right, and after only a few more steps, it again vanished. She stepped forward a few feet and the wall resumed. She had discovered a side passage. A few feet later, she found another, and then another after that. With excitement, she realized that she knew where she was. The Russian had written about this place: a sort of hub, a round room with passages leading in all directions. According to him, the hub lay halfway between the palace and the exit on the far side of the wall. One of these passages, then, should lead beyond the walls. But which one?
Sofia turned around and counted until she was back to the passage that she had come down. It would be easy to get lost: she imagined herself stumbling about from passage to passage in this darkness, alone, until she died. She wanted to press on, but first she needed to think. She closed her eyes, trying to clear her mind, when she heard a sound: a distant clank, as of metal banging against metal. Then nothing, only her breathing and the loud beating of her heart. Her every instinct told her to turn and run back to the palace, but she would be a fool, she told herself, to run because of a mere sound. Besides, if the Turks were there somewhere in the darkness, they would no doubt have torches, and their eyes would not be adjusted to the darkness. She would see them long before they saw her.
She bent down and placed the book at the mouth of the passage, with her candle on top of it. Then she turned and again followed the curving wall. She paused at every side passage she came to, listening hard for any sound, but heard nothing. The room was immense, and she quickly lost count of the number of side passages. She had begun to fear that she was moving in circles, when finally, she stopped before the mouth of a passage and felt a warm wind ruffle her hair. The draught of fresh air was steady. Somewhere ahead, this passage led to the outside world.
She had only gone a few feet down the tunnel when she heard the clanking again, louder and closer this time. She froze as the hairs on the back of her neck stood up. Sofia listened, holding her breath to hear better. The noise did not repeat itself, and she continued on her way.
The passage began to slope upward. She picked her way forward, pausing frequently to listen, but the clanking noise did not repeat itself. At every step she half-expected a band of Turks to spring forth, but there was nothing, only the continuing darkness. She estimated that she had walked some one hundred feet when she ran into something solid. The sudden impact surprised her, and she jumped backwards, dropping into a defensive crouch. The clanging noise was back, loud and right in front of her. She waited, not daring to breathe, as the clanging slowly faded. When it was gone, she crept forward, her hand stretched out before her. She felt something: a metal bar, stretching from the floor towards the ceiling. Next to it was another, and then another. She grabbed the bars with both of her hands and shook. The clanking returned. She knew now what had caused it: a locked gate, rattling in the wind.
The Russian writer had not mentioned a gate, which meant that either it had been added after his trip through the tunnel, or she was in a different passageway. She felt the bars of the gate again. They had been spaced to keep out men in armour, but she might be able to fit through. She pushed her head through first, and then, turning sideways and holding her breath tight, she just managed to squeeze through. She continued down the tunnel into the darkness. She could hear a new sound now, a deep, repeated booming, which sounded to her like the heartbeat of the earth. It took her a moment to realize what it was: cannons. Eventually, the sound faded away. She could only guess what that meant. Had she passed them? Was she moving away from some exit that she had missed in the dark? Despite her doubts, she kept walking. A weak light began to fill the tunnel, and in the distance she spied a pile of large stones blocking the way ahead.
Sofia hurried forward. It looked as if there had once been a small room here, with stairs leading upwards – just as the Russian had described the exit from the tunnel. She dropped to her knees and moved among the fallen rocks, looking for a way through. Finally, she found it: a narrow passageway that wormed its way up through the rubble to where she saw a thin sliver of blue sky. She wriggled into the passageway, but after several feet, her progress was blocked by a large stone. Sofia shoved against it, and the stone shifted slightly. She braced her legs against the sides of the passage and pushed harder. This time, the stone rolled aside, revealing the blue sky beyond.
Sofia pulled herself upwards until her head poked out of the tunnel. She was on the side of a small hill, hidden by tall grass. The heavy, flat stone that had covered the tunnel entrance lay to the side. She looked about, but saw nobody. She wriggled the rest of the way out of the hole and crouched in the grass. Before her, empty hills rolled away into the distance. To her right was the final stretch of the Golden Horn. She turned around and edged her way up the hill. When she reached the top, she dropped to her stomach in the grass. Only a hundred yards in front of her lay the Turkish encampment, stretching away far into the distance, all the way to the walls of Constantinople. As the sun reached its zenith overhead Longo walked the walls alongside Dalmata, inspecting the damage wrought by the Turkish cannons. They started at the Blachernae wall, just north of the palace. This was the newest section of the wall, built in the seventh century to enclose the Blachernae quarter. Unlike the rest of the land wall, it was only a single wall, but it was thick and had held up well to the bombardment.
'The walls are stronger than I had imagined,' Longo said.
'Wait until you see the Mesoteichion,' Dalmata told him. 'It is where they have placed their largest cannons.'
They continued and crossed over on to the innermost of the Theodosian walls, built over one thousand years ago, in the early days of the Eastern Roman Empire. At first, the walls looked strong, but as they sloped down towards the Lycus river, gaps began to appear in the outer wall. By the time they reached the Mesoteichion – the area around where the Lycus river passed through the walls – the gaps had become the norm, and stretches of wall the exception. The inner wall was still more or less whole, but the outer wall had been almost completely destroyed. Longo stopped and looked down on the ramshackle stockade that had been built on the rubble. Dirt had been thrown on the debris to create a walkway, and then planks and sacks of earth used to create a low barrier. At the top, barrels filled with dirt formed a battlement, providing the defenders with some cover.