Update (october 2009): The Norwegian fjord region has again been rated as the best tourist destination in the world, according to votes in a National Geographic panel.  One panelist called the fjords "about as good as can be done."

A fjord is a narrow inlet of the ocean, fjords are essentially U-shaped valleys flooded by the ocean (not gorges or rivers as sometimes assumed). Fjords is the most dominant topographical feature of western and northern Norway. But fjords are important in other parts of the country: Oslo sits at a major fjord, the Oslofjord, Trondheim also sits at the shores of a large fjord. 

Fjord terminology: Beacuse saltwater fjords runs from the ocean deep into the interior, locals say "in" the fjord when they travel away from the ocean, and "out" when they sail (or drive) towards the fjord mouth. Locals will be confused if visitors for instance say "sail up the fjord". Up and down only refers to mountains, rivers and valleys (or latitude).

Although most fjords are relatively narrow, they are generally so deep that crossing is only possible by ferry or boat. This means that there is large number of ferries in this region. It also means that the largest cruise ships can enter even the very narrow fjords. Valleys are typically extensions of fjords into the hinterland, in these valleys there are often deep lakes echoing the fjord below. The scale of a major fjord like Sognefjorden, is like the Grand Canyon in the western USA. Because fjords are extensions of the ocean they contain salt water, but due to the numerous rivers the salt content of the top layer is notably lower than in the Atlantic.

Although there are fjords all over Norway few are so spectacular and accessible as those in Western Norway (Northern Norway also have a large number of nice fjords). The characteristic fjords of western Norway are deep (often much deeper than the ocean at the mouth of the fjord) and walls (hills along the fjords) are steep and decorated with lush vegetation and tall waterfalls. Several of the world's longest waterfalls can be found in western Norway, many of them plunge directly into the fjord. The further away from the ocean, the deeper and more dramatic the fjord (Sognefjorden is more than 1000 meters deep). Along the coast, fjords may be indistinguishable from straits or sounds between the numerous islands.

Nærøyfjord, Flåm and Geirangerfjord are probably the most famous in the western fjord region, although these places are spectacular visitors should note that a large number of fjords are equally nice. The typical western fjords are found (roughly) from Stavanger to Kristiansund in the north-west. Many fjords in Northern Norway (Nordland and Troms counties), are similar to those in the western region. In total the fjord region then covers more than 2000 kilometers.

In Eastern Norway, a number of lakes are also called fjords, although these are also fjords in a strict geological sense and are in fact very similar to western fjords, they contain freshwater. In Western Norway there is also a large number of very deep freshwater lakes (like Hornindalsvatnet), typically at the end of a long fjord. The word "fjord" ("j" pronounced "y") is Norwegian but related to words "ford" and "firth" in English, and "furt" in German.

National geographic magazine rated the fjords of West Norway as the world's best tourist destination, Geiranger and Nærøyfjord also obtained top score among UNESCO world heritage sites, quote:

"The West Fjords have sensational scenery, are well-preserved and are clean. The people there are willing and helpful. There are great outdoor activities, and good hotel options and restaurants, but they close rather early! In May-June there's no feeling of mass tourism, visitors can just take ferries like normal Norwegians going about their business."