National Geographic has always been a great resource for education. National Geographic has an entire education site for teachers.
The site has teaching resources, lesson plans, activities, links, reference, news, multimedia, and much more.
The activities include NatGeo video clips, objectives, standards, vocabulary, and much more.
This is a great resource for any teacher to use, as topics range from the environment, to science, to social studies.
Here's an example of what an activity page looks like: