World Hello Day - November 21, the 1973 Peace Challenge greeting across barriers
World Hello Day on November 21 is an annual global observance started in 1973 by Brian and Michael McMahon during the Arab-Israeli war. Anyone to greet ten people on the day, regardless of organizational, political, religious, or other differences. Not a public holiday.
International observancePublished October 14, 2026
- Observed in
- UN
- When
- November
- Frequency
- Same date every year
- Days off
- Varies by country
- Public status
- Varies by country; consult local government gazette
World Hello Day on November 21 is a global observance founded in 1973 by Brian and Michael McMahon during the Yom Kippur War as a one-day protest against misunderstanding between peoples. Participants are asked to greet at least ten people regardless of organizational, religious, political, or other differences. Not a public holiday.
The one-line summary
Annual November 21 observance started in 1973 by Brian and Michael McMahon. Goal: greet ten people regardless of differences. Observed informally in 180 countries. Not a public holiday.
Origin and history
World Hello Day was founded in 1973 by Brian McMahon, a Harvard graduate and Arizona State University professor of speech communication, and his brother Michael McMahon, a physician in Medford, Massachusetts. The brothers founded the day in response to the Yom Kippur War, which they felt was being worsened by a lack of personal communication across conflict lines. Their proposal: for one day, everyone should greet ten people they would not normally greet, regardless of differences.
The McMahons initially wrote to government leaders in 90 countries, asking them to participate. The first year, 15 countries sent back confirmation of participation. By 1978, the list had grown to 85 countries, and by 2001 (the year of the Nobel nomination) over 180 countries were reportedly participating. The day has been observed every year since 1973 and has survived the brothers' passing (Brian McMahon died in 2002).
How it is observed
The official ask is simple: greet ten people on November 21 regardless of organizational, religious, political, or other differences. The McMahon brothers framed the day as accessible to anyone, anywhere, with no special equipment or preparation. Schools mark the day with classroom exercises on communication, peace clubs, and letter-writing to pen pals in other countries.
Peace and interfaith organizations use the day to launch larger initiatives: reconciliation meetings between estranged groups, joint worship services across denominations, cross-border video calls between schools, and cultural exchange events. Some media outlets print a "Hello Day greeting card" in their November 21 print editions for readers to cut out and use.
Global participation
The McMahon brothers and the World Hello Day Committee (a small foundation they established in Arizona) claim participation from 180 countries, with greeting cards sent in 32 languages and an estimated 50 million total participants annually. The greeting card program was active until 2010; the McMahon brothers distributed over 20 million free greeting cards in the program's first 25 years.
Controversies and criticism
World Hello Day has faced mild criticism for being too minimal a gesture to address the conflicts it claims to address. Critics note that a single greeting on a single day does not address structural causes of conflict. The McMahon brothers' response was always that the day is a "first step" - the symbolic value of personal communication is the foundation for broader reconciliation.
Some critics have also noted the day overlaps with UNESCO's World Television Day (also November 21), creating confusion between the two observances. World Hello Day predates the UN designation by 23 years.
Related observances
November is a month packed with global observances: World Television Day (Nov 21, UNESCO-designated), World Kindness Day (Nov 13), World Philosophy Day (Nov 15, UNESCO), and International Day of the Girl Child (Oct 11). World Hello Day is the only one with a direct founding story tied to a single conflict.
Sources
World Hello Day CommitteearchivesBrian McMahon obituary2002UNESCO World Television Day1996Arizona State University faculty archives1973