The origins of Greenpeace began with a concert, a voyage, and a mission to end nuclear weapon tests. In 1969, a group of protestors held an unsuccessful peaceful protest in an attempt to prevent the U.S. from detonating a test bomb in Amchitka, Alaska. In 1970, these protestors establish their own group -- the Don't Make a Wave Committee -- and organized a benefit concert to raise money to fund a voyage to Amchitka. The ship was named Greenpeace by activist Bill Darnell, and it set sail in 1971. Due to an interference by the U.S. Coast Guard and bad weather, the Greenpeace crew had to cut their voyage short, but their trip still garnered national attention, causing many Americans to become angered with the government's actions. Because of the widespread criticism, the U.S. decided to discontinue their nuclear tests.
Although it was still under the name of the Don't Make Wave Committee, this protest voyage is considered to be the beginnings of Greenpeace. The group officially changed their name to Greenpeace in 1972. The Greenpeace website lists the founders to be Bob Hunter, David McTaggart, and Dorothy and Irving Stow. Their second campaign targeted French atmospheric weapons testing. In the mid 1970s, Greenpeace began to expand the scope of its efforts, focusing on issues such as commercial whaling, seal hunting, and toxic waste. Around the safe time, independent Greenpeace groups began to surface throughout the globe. In 1979, Greenpeace International was established, and it set up a formal organizational structure that linked the local offices.
A set of comprehensive timelines covering the activities of Greenpeace in the past few decades can be found here: https://www.greenpeace.org.uk/about/impact/history/
The 1980s saw an increase in Greenpeace ships and offices throughout the world, and activism efforts were still focusing on nuclear weapons, toxic waste, and destructive whaling, seal hunting, and fishing practices.
The 1990s marked the beginning of Greenpeace's climate change campaigns.
In the 2000-2010s, Greenpeace expanded their activities to focus on a broad range of environmental issues, including pollutants, wars, hazardous chemicals, deforestation, coal, and oil rigs.
Greenpeace is an international organization, and it's international office is based in Amsterdam. Greenpeace has 55 regional offices all over the planet. These offices function independently, and although they often carry out global campaigns, they often times are based on local issues. Regional offices also seek out funding from donors for their activism activities. Supported by a "consultive international decision making process", Greenpeace International monitors the coordination of the various regional offices' global strategies. Other roles of Greenpeace international include assisting in activism efforts in countries that do not have a Greenpeace office, creating new regional offices, fundraising, providing IT assistance, and protecting the Greenpeace trademark.