Google Maps now allows users to visit landmarks around the world from a computer. The feature was added Wednesday, April 25, and allows for 3D tours of famous landmarks.

There are more than 15,000 sites around the world to view. Some are New York's Central Park, Yosemite National Park's Half Dome, the Buckingham Palace in London and the Trevi Fountain in Rome among others.

It's easy to start a tour - just search Google Maps for a landmark and the left-hand side of the program will reveal if 3D photo tours are available. Google has also provided a handy link which shows all of the available tour spots. Users need to turn on Map's WebGL feature which allows 3D viewing without additional software.

"To produce these photos, we use advanced computer vision techniques to create the 3D tours from public, user-contributed photos from its Picasa and Panoramio photos [the latter is a photo community Web site owned by Google]. We start by finding clusters of overlapping photos around major landmarks. From the photos, our system derives the 3D shape of each landmark and computes the location and orientation of each photo. Google Maps then selects a path through the best images, and adds 3D transitions to seamlessly guide you from photo to photo as if you're literally flying around the landmark and viewing it from different perspectives," Google said in its blog post on the feature.

3D tours is just one feature Google is adding to improve its products. The company released the 6.5 update for the Android version of Google Maps, which brought high-pixel-density resolutions to the app. A revised Navigation home screen for Ice Cream Sandwich devices was released to make it easier to enter new destinations from recent or favorite locations by swiping left or right. The update also allowed users to prioritize means of transport.

Due to the photos being user contributed, adding more photos increases the quality of the tours. Making photos publicly available on Picasa and Panoramio makes them eligible for inclusion.

(reported by Jonathan Charles, edited by Dave Clark)