2040 (MMXL) was a leap year starting on Sunday of the Gregorian calendar (dominical letter AG), the 2040th year of the Common Era (CE) and Anno Domini (AD) designations, the 40th year of the 3rd millennium, the 40th year of the 21st century, and the 1st year of the 2040s decade.
Events
- Terraforming of Gliese 876C begins.