Christer Sundberg (Sweden):
The town of Alta is not what-so-ever worth a detour. Spread out over 5 km with not less than three centres it could certainly pose as the Norwegian equivalent of one of those remote villages in an American road movie where the hero ends up in after having taken the wrong turn on the highway and gets tangled up in a weird story.
Not that I had any bad experiences in Alta but it just was not my kind of town. I also understood that the people living through the long and cold winters up there actually get a tax deduction for their heroism. Bless them all…
The rock carvings on the other hand, are worth a detour! If you happen to be in the neighbourhood, start with the excellent museum, café and souvenir shop all-in-onet before you embark on a long walk pass the many carvings. Some of them are over 9000 years old and once made by the Komsa culture back in the stone- and bronze age. And there are thousands of them….boats, reindeers, bears, fish, birds, elks, women and men, children, hunting scenes in an endless row. And its all up to your own imagination what they really means and tells. No one has really managed to explain them fully. Date posted: February 2006 Paul Tanner (UK):
There are (at least?) 4 different WHS solely devoted to prehistoric rock carvings – Alta (Norway), Valcamonica (Italy), Tanum (Sweden) and Coa Valley (Portugal)- Bhimbetka in India I think is all rock painting rather than petroglyphs. I have been lucky enough to visit the first 3(and some others – for instance those at Cholton Ata on the Kyrgyzstan Tentative list). I am no expert on the subject (Have a look at http://rupestre.net/ for an entrée to the world of Rock art) and would not attempt to judge between them on grounds of artistic merit or historical significance – all are worth visiting but perhaps the site at Alta is the most atmospheric. The carvings overlook Alta fjord - way inside the Arctic Circle. If you have driven here from Southern Norway you have come a long long way – and it feels it. Just driving round this enormous fjord on the way to the North Cape is a half day drive!
The Norwegians (as have the Swedes) have decided to highlight the carvings with a dye (the Italians have not) this makes them clear and easy to see. All are close together on a series of ice-smoothed rocks. Apparently they date from around 4200 – 500BCE. It is nice to think of ancient peoples passing the time by recording their daily lives and beliefs whilst looking out over that same fjord view which even today shows few signs of modern life apart from a few farmsteads (although the sea level was apparently somewhat different then - higher I believe because of Isostatic rebound (??) - and the rocks were therefore closer to the shore)!  
Have you been to Rock Drawings of Alta? Share your experiences!