Cádiz sits down in the southwestern corner of Spain, and it's one of those places where the history just piles up on itself. Ancient ruins, grand cathedrals, old watchtowers still keeping an eye on the sea. I spent a few days wandering its narrow streets, and there's more packed into this small city than you'd guess from the size of it. Here are the sites I think are worth your time.

  1. Cathedral of Cádiz

This is the one you'll recognise from postcards. A big Baroque cathedral that took a while to finish, to put it mildly. They broke ground in 1722 and kept at it for more than a hundred years, which is why you'll spot shifts in style if you look closely. The carvings are intricate and the artwork inside is worth lingering over, and then there's that dome, which just soars. Climb the tower if your legs are willing. The view over the rooftops is the payoff.

  1. The Roman Theatre

Tucked into the old town, this is one of the most significant archaeological finds in the city. It dates back to the 1st century BC. Think about that for a second. It could hold up to 20,000 people, and it hosted everything from theatrical performances to gladiator battles. You can walk the ruins yourself and pick up a fair bit about its history along the way. I found it easy to lose an hour here.

  1. Castle of San Sebastián

Out on a small island at the mouth of the harbour, the Castle of San Sebastián is a 16th-century fortress built to fend off pirate raids. It's been restored beautifully, and you're free to poke around its towers and ramparts. To be fair, the castle itself is only half the reason to go. The walk out to the island, with the city on one side and the open sea on the other, is what stays with you.

  1. Torre Tavira

The Torre Tavira went up in the 18th century as a watchtower, the idea being to keep an eye on the harbour and whatever the sea brought in. These days you climb to the top for a sweeping look across the city and beyond. The real draw, though, is the camera obscura up there. It throws a live image of Cádiz onto a concave surface, and if you ask me it's a strangely mesmerising thing to watch.

  1. Oratorio de San Felipe Neri

Another old-town spot, this 18th-century church rewards anyone who slows down and looks. The decoration is ornate, the artwork is lovely, and there's a painting by Francisco de Goya hanging inside. But its real claim to fame is political rather than artistic. The 1812 Spanish Constitution was drafted here, right in the middle of the Napoleonic Wars. Standing in that room, knowing what happened in it, gives the place a weight you don't quite expect from a church.

  1. Plaza de las Flores

Right in the old town you'll find the Plaza de las Flores, a square ringed by colourful houses and those ornate balconies Cádiz does so well. Shops and cafés spill out onto it, so it's busy with locals and visitors both. And true to the name, there's a flower market selling blooms and plants. Grab a coffee, sit for a while, watch the square do its thing.

  1. Casa de las Cadenas

Last on my list, and easy to miss, is the Casa de las Cadenas in the old town. It's an 18th-century mansion, and the decoration inside is the reason to go. Beautiful frescoes, carvings done with real care. You can wander through the rooms and get a sense of the family that once lived here and the history the place carries.

So that's Cádiz, or at least the slice of it I managed to see. For a city this compact, it holds a remarkable amount of the past, from grand cathedrals down to Roman ruins you can still walk through. Whatever pulls you here, the art or the old stones or just the history of the place, you'll leave with a longer list of things you meant to get to. I know I did.