He took her to the origins of time, to the start of the universe, and he watched it burst to life in her widened dark eyes. There were tears of something that sat between sadness and wonder, perched and prepared to fall, but they were stilled by his unrelenting study of her and they dried away as he listened to her laughter and watched the way she talked. The words weren't important, though he stood there memorizing them anyways, and he smiled in response, waiting for her to reach for his hand to grab hold of, just for a moment.
"What if we started it; what if we started the universe by coming here? What if we're the big bang everyone's always going on about – we're the gods of legends who first lit the darkness – and the universe is a paradox in and of itself and we're just lucky it hasn't all collapsed – just waiting around for the day that it becomes too big and too bold and it does, and that's the end. Just like that."
He took her to see the Earth churning about before the first signs of life began to carve at her surface; gaseous atmosphere lit up with volcanic explosions and roaring angrily into space as it formed. She frowned then, a curious thought overtaking her mind as he waited, because she had to parse it out, had to find the right words, and when she looked up at him, she only offered a small grin and a simple shrug. It was the start of an idea that would fester about for days, he knew, and he simply sighed and returned to the console with a request for her to close the doors. She might have breathed then, a simple set of words muttered to herself, and he twisted away from the way they struck his ears.
"Don't think on the end, Clara."
He took her to the building of the pyramids and they walked across the sands, bodies baking in the hot mid-day sun as their clothes became peppered with granules he knew would take effort to remove. She held tight to his arm and they made their way around quietly, a surprising feat for him, she'd commented, and they found themselves sitting at the top of construction, looking out at the stars shooting through the night sky. He'd leaned back against his palms on the coarse rocks to watch her lay down across the stones just beside him to laugh before she began to ramble, still slightly intoxicated by the wine she'd had with dinner.
"We're standing where one day no one will be allowed – do you know that – because of a simple slip of psychic paper in your pocket, Doctor. I love this. Travelling with you. I love everything about travelling with you. Everything. Even... everything."
He took her to an island that sat in the middle of the ocean and told her one day it would be the origin of the story of Atlantis. They swam in lagoons and he shouted as she climbed trees and then laughed while they ran along the surf, bare feet kicking up chunks of wet sand and the froth left by waves. Collapsing underneath the sway of emerald green fronds, the Doctor looked to her face, spotted slightly with freckles, and he laughed. He allowed himself to laugh as she watched him, her brow furrowing as her head shook slightly. And then he sighed before going silent, smiling up at her. There were so many things he wanted to say in that moment, but he couldn't quite find the right words to express them.
"You're a strange man, Doctor, and one day I'll figure you out. But not today; today is the day I watch you get a sunburn on those bony legs of yours, which you should probably let out more often, I think I see veins. Do Gallifreyans have veins like us? Doctor, can you tan?"
He took her to Italy. He'd always promised to take her there and they sat in the Gondola with a short portly man pushing them through the canals as evening turned the sky purples and pinks. They sat together laughing giddily and the Doctor told her about Casanova and how he owed him a chicken, and she told him about how much she loved cannolis and eventually she reached for his hand, words leaving them both as she interlocked their fingers and waited until he closed his around hers and whispered her name. He dropped his forehead to hers and felt her sigh warmly against his lips just before he touched his to hers hesitantly, fearfully, delicately. Listening to the waters lap against the edges of the Gondola as they slowly moved along, the Doctor pushed his free hand into her hair as they met their foreheads again, breath mingling in the small space between them.
"Why does this feel like goodbye, Doctor?"
He took her to the end of time and the blackness of space and he watched her cry. Clara didn't explain the tears that rolled over her cheeks and dropped off her chin, caught up in the force field around the Tardis to float out into space. He didn't need to ask; she didn't need to say. Realization had settled in and she understood the world she shared with him was no longer real, merely a construct of a dying mind. Merely a comfort the Doctor provided as he stood by her side.
"We had a good ride, you and I, through all of time and all of space, just like you promised me. Lots of scares and near misses and enough pain to last a lifetime, but it's nearly done, so we'll not dwell on them, but we had so many good times, eh, Doctor? So many wonders out there in the universe; so many things I would never have seen without you So many. You know, I think I'll miss you terribly when I'm gone. I miss you already... am I gone, Doctor?"
He took her to his hearts. Eyes closed, lips trembling, hands holding their places on her temples as she began to disappear from life. He took her to the love that rested there, hidden away for safe keeping, and he gave it to her and he could hear her laugh as it overwhelmed her. He exhaled as those giggles began to fade and the connection between them – one that seemed to have existed from the moment he first met her – crackled away, leaving him feeling the lumpy dirt underneath his knees and the cold damp air burning his lungs. The Doctor's fingers slipped away from the warmth of her as he reveled in those final thoughts, stubbornly filled with so much hope, smiling sadly at the notion that all he'd been left with was an echo.