Tiwanaku

The admission fee for foreigners Bs 100. Locals pay Bs 15.
Getting there is rather easy. If you're staying in El Centro (the city), take a taxi to the cemetery (Cementerio), or any minibus with the "Cementerio" flap on the window. Across the street from the cemetery's main gate, there are florists, and to the right of this area are minibuses headed to Tiwanaku. If there's enough people, you shouldn't pay more than Bs15-20. If not, you either have to wait until more people show up, or have to pay more. Expect a 90-minute drive, buy some snacks and make sure the prices aren't too expensive for those either. Also, when the drivers head up to El Alto on the road to Tiwanaku, they will most likely pick up more passengers if the bus or minibus isn't full. There usually isn't much traffic on the road out of El Alto, so besides this, everything should be fine. Some drivers drive quite fast so they won't waste time, but they are experienced so don't feel too nervous. You might also want to choose to sit near a window or out of the sunlight.
On the road to Tiwanaku from La Paz you may want to visit Laja - a town at the original site of La Paz. Laja has big and nice church, and tasty local bread. The ride is 10 Bs. from La Paz. To go to Tiwanaku from Laja, return to the main road and catch a minivan there (ask driver to stop at Tiwanaku, as most other people may be heading to Peru).
You can also book a tour through the many tour operators in La Paz. Most of these appear to be in Spanish only.

This is where you should stay, nowhere else to go to. There are only small villages in the surrounding areas of Tiwanaku and the site around it. The small town center of Tiwanaku is located about 10min on foot from the archaeological site, but apart from a few shops selling basic groceries, soft drinks and cookies there's not much there, too.

Tiwanaku is the main excavation site of the pre-Incan civilization of the ancient Aymara. The Aymara had a vast empire that stretched from the Atacama Desert to Cochabamba and today's northern Argentina. This monumental city in the Bolivian highlands, 4,000 m (13,000 feet) above sea level and one of the around 1000 recognized World Heritage Sites, is considered to be the most important archaeological site in Bolivia. Tiwanaku is surrounded by mountain ranges, with Lake Titicaca on its west side (though not visible). The massive, solid blocks of a stone not indigenous to the flat plateau give rise to the site's nickname – "the Stonehenge of the Americas" – and, over the years, they have given rise to some otherworldly theories of how the site came to be. Even though the Inca invaders and later the Spanish colonizers used the huge rocks of the former city to paving their streets and construct buildings, large parts are still there and partly reconstructed. However, most of the archaeological site is still hidden beneath the surface, and research is in progress. At the museums, containing most of the things found at the site, taking photos is not allowed, but sometimes people take them anyway. The museums contain lots of pottery and handicrafts, and also a skeleton that is about 13,000 years old.
Be aware that while this pre-Inca site should principally be interesting, you might be in for a disappointment. Considering the relatively high price for foreigners and the fact that it's marketed as THE archaeological site in Bolivia, you would expect some proper presentation, signage, markings and museums, but in fact the site lacks far behind other similarly priced sites, and you keep wondering what they do with the money. The two tiny museums are badly maintained, and the handful of potentially very interesting ruins has such bad explanatory signs that you have literally no idea what it's all about.

Walk around, take photos, read the signs, visit the museums. Don't cross over signs or fences: you'll upset the security guards there and might be kicked off grounds. Otherwise, you have quite a lot of freedom there to walk wherever you want.

Many indigenous women will be selling pottery, scarves, clothes, crafts, and other handmade things. They do not really charge much, and some of the items are worth the price. Some weigh a couple of pounds, so when packing your luggage at the end of visiting Bolivia, put these things in your carrying bag.

There are a couple of restaurants near the museum. They are a bit expensive but the food is OK. Make sure to be careful eating fish or other seafood: They should be well cooked, especially since you're probably not a native.

You'll find people selling water and beverages around. At the restaurants, they have more variety.

• Hotel Akapana, with hot water, restaurant, and the owner speaks English. It is across the street from the Tiwanaku Museum and a five-minute walk to the ruins.

The altitude at Tiwanaku is similar to that of El Alto, around 4000 m. If your body didn't have time to get used to this yet when visiting Tiwanaku, it might be wise to consult the article about Altitude sickness.

• Visit Lake Titicaca at a 30-min drive; the boat ride is about US$5.
• Visit the Pariti Island with more ruins (not fenced, Aymara tombs and a ceramic museum - this is an all-day trip and can cost US$20-30).
• The Main Plaza, numerous sculptures around the plaza, a 400-year-old colonial Church, and ask the neighbors to show their personal monoliths, mummies, ceramics, their families decades ago. The Fernandez family in the main plaza has a original monolith (monolito Zunagua) in their back yard.