"If you asked anybody in Mars science to come up and give a talk discussing the discoveries and insights of the past 50 years you'd get as many different perspectives as as you had scientists." -Stephan Clifford 

Note that with formal hall lectures, there will be a hype-man that will read the speakers resume before the lecture starts. This one starts at 16:45. Feel free to skip to there. 

This is probably one of , if not the first lecture someone should review on Mars. Stephan Clifford is the Mars guy. Probably one of the best Mars planetary-scientists, and certainly the best lecturer. This lecture is three years old when I post this, and the most recent of Clifford's lectures. His previous lectures are different, meaning he never gives the same lecture twice, yet all are relevant. Five years is nothing to the progress of planetary-science.

This LPI is a catch-all lecture for Mars. It is a direct answer to the question; what are planetary-scientists really doing behind the ivory-paywalls? Turns out they are shifting the view of Mars dramatically from what it was before Pathfinder.

• At 19:20 Clifford is calling attention to a slide showing the ice-cap coverage with the seasons. This, like other things, such as Mars periodically tilting, are things everyone knows and no one thinks through. It will come up thematically in this lecture. Water (& CO₂) is getting to the south Noachian highlands with each season using only sublimation and frost. Keep that in mind.
• At 28:50 he calls attention to another tongue-in-cheek detail people seem to forget. Ice is very much a mineral, and on Mars it is often part of a sedimentary strata. What happens when the ice sublimates under the surface? 
• Slide at 34:50, Clifford drops some deeper questions regarding Mars. Contrary to what is sometimes believed, large Mars river channels usually lack any kind of certain tributary (smaller feeding rivers). But what Mars does have is a Noachian source and some weird "hummocky" terrain that the bigger flows seem to emerge from. All these bullets are connected. Sublimated glaciers and groundwater layers with an episodic influx of heat seems to be a large part of what forms these channels. In the image hes talking about, an obvious moraine is present, so glacial action is also involved.
• At 41:10 it is mentioned that Mars is believed to be younger than most other worlds in the solar system. It's possible that Mars had a resurfacing event. It's also possible Mars really is younger, or that it had an orbit too close to Jupiter for too long. Both of those last two options seem to be stronger, since Mars seems to be depleted of heavy elements even for it's size.
• From 47:20 on Clifford describes the growing rift between the old way of thinking about Mars and the current way. 

Clifford always has this soft-spoken subtlety in his presentations. He chooses words carefully so not to step on toes, but he will drop a sheathed-point pretty regularly. If your experience with Mars is poor, you may miss a lot of meaning in his sentences, but one of the best presenters to upgrade your experience with Mars is him.

Here is a bonus lecture from Stephan Clifford in 2017. Similar but not the same content.