Conservation International A field-based, non-profit organization that protects the Earth's biologically richest areas and helps the people who live there improve their quality of life.
Earthwatch Promotes sustainable conservation of our natural resources and cultural heritage by creating partnerships between scientists, educators and the general public.
Earthshots Before-and-after satellite images showing recent environmental events.
Environmental Defense
The Nature Conservancy Their mission is to preserve the diversity of plants, animals and natural communities by protecting the lands and waters they need to survive. Many of their programs and projects offer overnight accommodations, multi-day trips and tours.
The UNEP World Conservation Monitoring Centre was established in 2000 as the world biodiversity information and assessment centre of the United Nations Environment Programme.
Wetlands International Non-profit organization concerned with the conservation of wetlands and wetland species. It comprises a global network of governmental and non-governmental experts working on wetlands. Activities are undertaken in more than 120 countries worldwide.
The World Conservation Union  (IUCN) Brings together 111 government agencies and some 10,000 scientists and experts from 181 countries in a worldwide partnership promoting conservation around the world.  Created in 1948.
World Resources Institute Provides information, ideas, and solutions to global environmental problems. Their mission is to move human society to live in ways that protect Earth’s environment for current and future generations.