We visited Badajoz in September 2004 as part of our circular trip from Jerez via Cordoba, Toledo and Merida. We stopped for a few hours en route from Merida back to Jerez, walked up to the top of the hill, stopped near the cathedral for lunch, before heading off for the long drive (370km) down to Jerez
Badajoz is a large town sprawling over quite a large area south and east of the old centre. In the Peninsular wars, the town was surrounded by the walls, which still survive along most of their length. Wellington was only one general to lay siege to Badajoz. As it lies so close to the Portuguese border and on the key route from Lisbon to Madrid, it has been fought over many times from the Romans, the Moors and the Christians, and most infamously in the Spanish Civil war when defenders and refugees were massacred after the fall of the town.
Today, Badajoz is just a provincial capital. There are a few places worth visiting, but when we were there, there was a lot of building and restoration work going on in the old town. I have put a few pictures in a travelogue, but probably won't be writing any tips.