A battered ruin of a box took form in the battered ruin of a street. It would be two thousand years before anyone would think of inventing a box just like it, but it still felt at home in the cramped, high lane where it was now. It felt oddly reassuring in that tight space— like it was telling the world that things would look just as dilapidated in the millennia still to come. With a whump, its paint-stained shell grew solid in the air, and like a song fading in from the background the voice of a woman became clear.

"Brace yourself for the wonders of history!" it said. It's 73BC, and the weather feels warm and pleasant. And where we are will be a holiday destination for tourists for thousands of years. Prepare for the romance, the glory, and the wonder… of Ancient Rome!"

The Doctor flung open the doors of her TARDIS, and Chris and Lorna jumped out in delight. Their grins were huge as they emerged into the summer air of the past, then got smaller as they looked at what was there.

"This isn't Ancient Rome," said Chris. Rome's got columns, and the buildings are all white. This is muddy and all falling down."

"Ah, but that's the thing about this place! It lasts for a very long time. One of its rulers, he said he'd found it a city of brick and left it a city of marble. But that's all in the future still. This is just what it looks like at the bricky end."

"Oh," said Chris, looking disappointed.

"But it's still Rome!" said her Mum. "Full of sun, and history, and all sorts of fun things to see!

"We could go to the Colosseum!" said Chris.

"That hasn't been built yet," said the Doctor.

"Then we could see Pompeii!"

"That's in Pompeii."

"Oh. Well, we could meet the Emperor! As long as it's not one of the bad ones."

"There isn't an Emperor yet," said the Doctor. "That's all still to come. But Julius Caesar is around!"

"Oh!"

"He's not done much of anything yet. He'll be off in the senate, I expect, complaining about something dull."

Chris put her hands in her pockets, and looked glum.

"It smells in the past," she said after a while.

"Doctor," said Lorna. "It's very impressive, how we've gone back in time and all. But when you said we were going to Ancient Rome I imagined we'd see… gladiators, and Hadrian's Wall! But this, well. It doesn't even look like the books."

"History often doesn't. Holidays often don't! There isn't a picture of your house, is there, when you buy a postcard of Manchester?"

"But the whole point of a holiday," said Lorna, "is that you don't tend to spend it in your house."

"Well, we'll find a nice place to stay here," said the Doctor. "It's not all alleys and smells, even now. And I've got an app for this kind of thing." She produced her phone from her pocket and began to tap and swipe. "It's like Air B'n'B, but for the past. When a jobbing Time Lord needs somewhere to stay."

"You call yourself a Time Lord?!" said Lorna in disbelief, but the Doctor was totally absorbed in her phone. She pointed triumphantly in one direction and started to run in it, then pointed in a completely different direction and started to run towards that.

"Come on!" said! "Holidays await!"

"Let's go, Chrissy,"' said Chris's mother softly, "at least we don't have to pay for any of this."

They followed their tour guide into 73 BC, into a Rome quite unlike the one that they wanted to visit.