With close resemblance 10 years have expired since NASA's Opportunity Mars rover launched in July 2003, yet it just provided a ground for its first evidence of water on the Red Planet. The prominent fact that the water seemed not unnaturally strange being acidic, on the contrary drinkable water for humans in actuality. Even though, it’s not existing anymore, yet the minerals opportunity originated have a chemical signature that recommends that they were formed by neutral-pH water like we have here on Earth.
The combination of this one accompanied with similar results originated by curiosity on the other side of Mars, indicates to the planet having a life-sustaining at the same time Earth-like climate during the first billion or so years of its 4.6-billion-year beingness.
Image Source: NASA Opportunity Mars rover