NATO consists of 32 countries across North America and Europe.

How NATO works

NATO now includes 32 member nations—but how does the alliance actually function? This explainer breaks down its structure, decision-making process, and funding model. From its founding in 1949 to its collective response after 9/11, here’s how NATO operates on a global scale.

NATO was formed in 1949 to deter Soviet expansion, prevent European militarism, and encourage political integration.

Members decide to what extent they respond to an attack on an ally

The NATO constitution is intentionally vague about what exactly is required from its members. Explore the historical debates and learn more about common misconceptions about NATO’s common defense clause.

Finland and Sweden joined NATO after Russia's invasion of Ukraine

In response to Russia's 2022 invasion of Ukraine, Finland and Sweden abandoned decades of military neutrality to join NATO, marking a major shift in Europe's security landscape and expanding the alliance to Russia's borders.

Watch the historic treaty signing that established NATO in 1949

NATO was created with the signing of the North Atlantic Treaty on April 4, 1949, in Washington, DC. The clip embedded in the webpage includes a newsreel with an excerpt from US President Harry Truman’s speech celebrating the historic day.

The treaty's Article 5 requires mutual defense, but not necessarily military action

Article 5 of the North Atlantic Treaty established NATO’s principle of collective defense. This resource examines the historical context, legal interpretations, and practical applications of this commitment, including its sole invocation after the Sept. 11 attacks.

How NATO responded to 9/11

The collective defense clause of the NATO constitution has only been invoked one time: after the 9/11 terrorist attacks against the United States. This video explores the immediate actions NATO took to respond to the attacks to support the United States. These firsthand clips from 2001 give a sense of the magnitude of the moment and the difficult decisions facing NATO leaders at the time.

As of 2025, every NATO member spent at least 2% of GDP on defense, a target the alliance had been pushing toward for over a decade.

Decisions at NATO are by consensus and must be unanimous

There are two strategic commands in NATO: one in Europe (Supreme Allied Headquarters Command Europe) and another in Norfolk, Virginia (Allied Command Transformation). The alliance is headed by both a military officer and a civilian leader.

The alliance operates under a "flexible response" doctrine—that is, proportionality

NATO countries' main deterrent against aggression is their ability to respond with nuclear weapons. This video from "The Infographics Show" outlines the purpose of this nuclear arsenal, NATO’s strategy to prevent attacks, and its plans in the event of escalation toward nuclear war.

Tensions between the US and European NATO allies

The Associated Press article discusses US Defense Secretary Pete Hegseth's assertion in February of 2025 that restoring Ukraine's prewar borders or NATO membership for the country are both unrealistic. This represented a large rift between the United States and its other NATO allies, prompting concern about America’s commitment to the future of the alliance.

NATO's Article 5 has been invoked once—after 9/11

The article was invoked the day after the attacks and launched a series of NATO campaigns to fight global terrorism. This page includes excerpts from a speech by then-NATO Secretary General Jens Stoltenberg about the attacks and the organization’s response.

193 nations are members of the United Nations

The UN's Member States webpage provides an alphabetical list of all 193 member countries, along with the exact dates they were admitted. Take a look at how the UN has expanded over time and understand each nation's place in the global organization.

NATO condemned Russia's 2022 invasion of Ukraine

While Ukraine is not a member, NATO responded forcefully to the Russian invasion of the country in 2022. This page from the NATO website offers answers to frequently asked questions about NATO’s response to the invasion, specifically on how NATO is aiding Ukraine.

National Hockey League, explained

Founded in 1917, the NHL started with four Canadian teams and now spans 32 franchises across North America. Its iconic Stanley Cup, first awarded in 1893, remains a unique prize, with winners' names hand-engraved each year. The league generates billions in annual revenue, aided by key expansions, lucrative TV deals, and global fan engagement. While player safety and labor disputes have posed challenges, the NHL remains a cornerstone of professional sports, offering an 82-game season culminating in the fiercely contested Stanley Cup Final.

There are 32 teams in the NHL

Click a team to see their current record and opponent for the day; read the latest news, including injuries; view the remaining schedule; scan where the team is in the divisional standings; review the current roster; skim all the player and team stats; and watch the latest video highlights.

The 1955 Warsaw Pact was the Soviet Union’s answer to NATO

The pact included Albania, Bulgaria, Czechoslovakia, East Germany, Hungary, Poland, Romania, and the USSR. The pact established collective security and a joint military command between the member countries.

NATO leads cyber war games in Estonia

Estonia is host to one of the world’s largest annual interactive cybersecurity drills. Russia is always considered the main threat, but this year, the war in Ukraine has only added to the stakes.

The Cold War (1947-1991) prompted the birth of NATO and the Soviet Warsaw Pact

The geopolitical rivalry between the United States and Soviet Union was considered “cold" because the two countries never directly engaged in military combat during the time period. This page from the Kennedy Presidential Library outlines the causes and major events of the early Cold War.

The 2026 FIFA World Cup will feature 48 teams, making it the largest field in World Cup history.

General Jennie Carignan was the first woman to lead a NATO mission

"NATO Through Time" is a podcast exploring NATO's history and its impact on today's world. This episode features General Jennie Carignan, Canada's top military leader, as she shares insights from her NATO missions in Bosnia, Afghanistan, and Iraq.

Explore the countries with a federal system—and see how they work

This resource from the Forum of Federations catalogs the world's federal countries. It provides background information on each, including the emergence of federalism, the division of power, and the practical interaction between national and regional governments.

The Big Ten is the oldest Division I collegiate athletic conference in the US

Established in 1896 with seven members, the Big Ten has expanded far beyond its Midwestern roots. As of 2024, it includes 18 schools—stretching coast to coast from Rutgers in New Jersey to UCLA in California.

The National Security Council advises the president on foreign policy and national defense

Created in 1947, the NSC coordinates military, diplomatic, and intelligence policy matters. Chaired by the president, it includes key Cabinet officials and senior advisers who shape American responses to global crises and security threats.

Ukraine has received over $300B in Western military and financial aid

Although not a member of NATO, Ukraine has received substantial support from Western nations, primarily the United States and the European Union, totaling more than $300B in military, financial, and humanitarian assistance.

See how global nuclear arsenals surged—then shrank—by country since 1945

Worldwide nuclear stockpiles peaked at over 60,000 warheads in the mid‑1980s during the US-Soviet arms race. Today, about nine nations collectively maintain roughly 12,000 warheads, with Russia and the US still holding the majority.

Mapping the world's 25 largest stock exchanges

Totaling a market capitalization of $106T (as of 2023), this map identifies the major stock exchanges worldwide on a map, ranking them by total market value. Nearly half of that value is located in the Americas.

Map of union membership by state

In the United States, unions exist across the entire country, but some states have more union members than others. Multiple reasons exist: from policy differences across states, to industrial and cultural influences. Want to learn more? Find out which state has the highest percentage of union membership, and which one has the lowest, through this map.

Wartime conferences exposed cracks in the US–Soviet alliance

At the Tehran, Yalta and Potsdam Conferences, Allied leaders coordinated WWII strategy—but deep disagreements over postwar Europe foreshadowed the Cold War. The USSR’s push for influence in Eastern Europe clashed with US and British calls for self-determination.

The Arab League has 22 members and very little enforcement power

It was founded in Cairo in 1945 and spans 22 nations across the Middle East and North Africa, ostensibly to coordinate policy on economics, culture, and defense. Its charter says any resolution only binds states that voted for them, rendering most of them toothless.

Cold War summary on a map

The Cold War spanned much of the world, going far beyond the main territories of the principal players: the US and the Soviet Union. This video map shows where the action took place, from the wars in Southeast Asia to the Suez Canal in Egypt.

The 1941 Atlantic Charter was a World War II alliance and model for the UN

The Atlantic Charter was a pivotal 1941 agreement between Franklin D. Roosevelt and Winston Churchill, outlining shared goals for a post-World War II world rooted in freedom and self-determination. These ideals later inspired the founding principles of the United Nations.

The National Guard serves both state governors and presidents

Roughly 430,000 trained military personnel act as a strategic reserve for the US military, deployed domestically during natural disasters or unrest as well as overseas. It consists of the Army National Guard and the Air National Guard, overseen at the federal level by the National Guard Bureau.

Questions about the US' commitment to its allies may have sparked a new nuclear age

Some US allies—from Warsaw to Seoul—are reevaluating their security amid doubts over American nuclear commitment, signaling the possibility they may want to acquire their own weapons.

Explore a map of data centers worldwide

As of February 2026, the US has more data centers (over 4,000) than the next 15 countries combined, thanks to years of investment by cloud service providers and technology companies. The next largest data center footprints come from the UK and Germany, with about 500 facilities each, followed by China with about 370.

Nearly 90% of the world's 12,321 nuclear warheads are held by Russia and the United States.

Federal systems are a minority among the United Nations' 193 members

Of the United Nations' 193 member countries, roughly two dozen use a federal system, dividing power constitutionally between national and subnational governments. This group includes the United States, India, Canada, Germany, and more. The video walks through examples of how these states operate.

The 'Original Six' era between 1942 and 1967 is known as NHL's golden age

Shortly after the National Hockey League formed in 1917, the league expanded rapidly for a decade. But as the effects of World War II took their toll on the country, NHL teams were unable to stay afloat. By 1946, only six teams remained. Using historical photos, this video recounts the teams that survived and shows what hockey looked like during the "Original Six" era until it ended in the 1960s.