Chesapeake Bay Bolide: Modern Consequences of an Ancient Cataclysm.
There is no consensus on the definition of a bolide, but it is an extraterrestrial body, which impacts the earth, explodes, and creates a crater. This site explains the consequences of the Chesapeake Bay impact.

Chesapeake Bay Impact Crater.
From the US Geological Survey, this site includes news and highlights, a list of publications and links to online publications, open-file reports, fact sheets and information on other earth impact craters.

Krakatoa: Volcano of Destruction.
From the Discovery, this site provides a detailed history of the volcano plus videos, puzzles, a virtual volcano and an option to build your own eruption.

Tour of Geologic Time.
From the University of California Museum of Paleontology, you can start in the Cenozoic Era (65 million years ago to the present) and work back through time, or start with Hadean time (4.5 to 3.8 billion years ago) and journey forward to the present day. You will be able to learn about the stratigraphy, ancient life, fossil localities, and tectonics of the various time periods.

Volcano World.
A project of the North Dakota Space Grant Consortium, this site includes information about the most current volcanic eruptions, history of past eruptions, headlines, features, and articles about myths and legends associated with volcanos.

Volcanos of the World.
Many videos about volcanic activity of Stromboli, Etna, Ol Doinyo Lengai, Erta Ale, Karimski and other volcanos.