The Newspaper Archive Map

Ancestry's Newspaper.com claims to be the largest online archive of newspapers. The archive includes searchable articles from over 21,000 newspapers dating back to the 1700's (although there seems to be a distinct bias towards English language newspapers). 

Using Newspaper.com's interactive map you can search for historical newspapers by location and by date. If you pay to subscribe to Ancestry you can then read the digitized articles. A similar service exists in the UK at the British Newspaper Archive, which allows you to search archived British newspapers for free but only allows registered users to read actual digitized content from the archived papers. 

The NewspaperArchive provides a similar subscription service to Newspaper.com, allowing you to search 'billions' of newspapers from around the world.Again you can search the archived newspapers for free but you need to register to actually view and read the archived articles. 

You can search and read through 129 years of New York Times back editions on the newspaper's TimesMachine website (again a subscription is needed). Using the TimesMachine's interactive interface you can read the Time's contemporary accounts of historical events, including the shooting of President Lincoln, the sinking of the Titanic and the landing of the first men on the moon.

By using the zooming and panning controls used by interactive mapping platforms, the New York Times provides users with familiar navigation controls with which to browse through its historical archives. The TimesMachine relies on panning, zooming and the click & drag method that web users are familiar with from using mapping platforms, such as Google Maps.

Wikipedia also maintains a list of online newspaper archives. This list includes links to both free and paid archives of newspapers around the world. The Wikipedia introduction to its list also includes the handy advice that some local library services may have subscriptions to newspaper archives which you may be able to access for free if you have a library card.

One other option is to explore the archives of still operating newspapers. The Newspaper Map provides direct links to thousands of newspapers currently operating all around the world.