NASA's Mars Curiosity rover. It took eight months for the rover to get to Mars, but the history of Mars exploration is much longer. To help readers get a sense of the history and development of Mars exploration, the Guardian has published a small interactive timeline of Mars exploration.
Mars Exploration Since 1964 is a timeline shaped as an orbit of Mars. Clicking on the dots along the orbit reveals a picture and some brief information about Mars exploration.
CNN offers a slideshow that explores the modern history of Mars exploration.
NASA Explores the Red Planet is also a must-bookmark for all things Mars. On NASA Explores the Red Planet you will find animations, videos, and graphics all about NASA's explorations of Mars.