1999 World Events · Post-Cold War transition and asymmetric shock
Columbine High School massacre
Two students attacked their Colorado high school with firearms and improvised explosive devices, killing classmates and a teacher before suicide.
Evidence-led reading
What is stated, why it matters, and what remains uncertain
What this is
A specific-event record selected from the protected World Events source ledger for cross-year research. It is not an exhaustive account of 1999.
Why it matters
It became a reference point for school security, copycat risk, and domestic lone-actor threat assessment.
What is established here
The page faithfully exposes the submitted record and its source boundary. No claim-level evidence packet has yet upgraded the record beyond a research starting point.
What remains uncertain
Starting-point source from the submitted dataset; verify exact dates, attribution, legal posture, casualty figures, and current status before reuse.
Record narrative
Source-bounded summary
Two students attacked their Colorado high school with firearms and improvised explosive devices, killing classmates and a teacher before suicide.
It became a reference point for school security, copycat risk, and domestic lone-actor threat assessment.
Structured fields
Record at a glance
- Stable record ID
- 1999-005
- Date or period
- 1999-04-20
- Type
- Lone-actor / mass casualty attack
- Focus
- Lone-actor attack
- Impact scope
- National
- Priority
- 4 of 5
- Location label
- Littleton / Columbine, United States
- Coordinate precision
- Site-level approximate coordinate
- Actors named by the source record
- Eric Harris; Dylan Klebold; students and staff
- Verification state
- source-start-point; sensitive details require independent verification
Geographic context
A coordinate locator, not a surveyed event footprint
The submitted record supplies 39.6039, -105.0750 with the precision label “Site-level approximate coordinate.” Multi-location events, disputed borders, campaigns, and broad regions cannot be reduced to one point.
Review location and coordinate boundariesSource and verification boundary
This remains a starting-point record
Starting-point source from the submitted dataset; verify exact dates, attribution, legal posture, casualty figures, and current status before reuse.
Citation and correction
Use the stable record ID and challenge individual propositions
A correction may concern the date, place, actors, attribution, legal status, figures, coordinate precision, source characterization, or why-pivotal summary without invalidating every other field.
2IA — International Intelligence Archive. “Columbine High School massacre.” World Events record 1999-005. Reviewed July 27, 2026. https://2ix.org/world-events/1999/1999-005/