La Paz is not the capital of Bolivia (that's Sucre) but it is the legislative capital and home to President Evo Morales and Parliament. La Paz has a large Aymara community, the indigenous people of the Bolivian and Peruvian Andes.
It's also possibly the most chaotic and busy city I've ever visited. It reminded me a bit of Naples in Italy. In much of South America, people use taxis or micros (minibuses which plough a particular route through town) to get around. There's no room on the pavements because of the amount of people waiting for the micros and you can't walk in the streets because of the amount of micros jostling for space, often fitting 2 lanes into what should be a 1 lane street. The drivers assistants in the micros constantly shout their routes out of the window and beeping your horn appears to be mandatory at least once every 60 seconds so walking along a busy city street is not the most tranquil of experiences. I suspect my hostal was possibly on the busiest, most chaotic street in La Paz.

I stayed 3 nights and wandered around the Plaza Murillo where the Presidential Palace, Parliament building and Catedral are. It was covered in pigeons and people eating ice cream and reminded me a bit of Trafalgar Square.
I visited the Mercado de Hechiceria - the Witches Market near my hostal. The stalls are full of good luck talismans, dried llama foetuses (no, I'm not sure what these are used for) and offerings for the gods - usually coloured sweets and little plastic toys arranged around a bottle of rum or other alcohol. The gods seem to have some strange tastes in Bolivia.
I visited an art gallery and the Museum of Folklore and saw ceramics, ponchos, feather head-dresses and lots of masks used by various ethnic groups in Bolivia as part of their celebrations.
I took a tour round the pre-Colombian ruins of the city of Tiwanaku from around 1500BC, which, although they were interesting I think I've been spoilt by the quality of the other ruins I've seen in recent weeks

I'd stayed in La Paz for about as long as I could cope with it so on Saturday evening I caught a 12 hour overnight bus to Uyuni in the south west of Bolivia.