river delta perhaps hold the signs of ancient life. but it will take a little while for the rover to get there, about three months. kristen fisher, cnn, washington. hello again, everyone. thanks for joining me. i'm fredricka whitfield. we begin with this breaking news. ukraine's president zelensky a short time ago calling for a diplomatic solution to the threat of a russian invasion as tensions in the region rise. but he also added he doesn't know what russian president vladimir putin is going to do next. zelensky is attending a key global security conference in munich today and spoke with cnc cnn's christiane amanpour. >> i'm not sure how many people expected you to leave your country and come here today. what was so important for you to be here? and what do you know about