ESO/M. Kornmesser
The agency is being rather mysterious about the whole thing, providing no further details about what the findings entail.
However, some outlets are speculating - judging from the panel of speakers - that this "major" finding could be the first evidence of liquid water flowing on the Martian surface.
One of the speakers is Lujendra Ojha of the Georgia Institute of Technology in Atlanta who discovered "possible flows of salt water on Mars," back in 2011.
Ojha joins a host of other big NASA names on the panel including Jim Green, director of planetary
NASA has sent multiple rovers and satellites to investigate the surface of Mars both on the ground and from space. The only evidence of water on the surface is in the form of ice due to Mars' sub-zero temperatures.
If there is liquid water, chances are it is flowing underground. You can watch the announcement live on NASA TV or using the video below: