Well, not to (slightly) derail the Thread from Baikal specifically, but terr ain features could provide Unique resources or better sources for ordinary resources.
Examples:
The above-posted Lebanese Cedars could be a particularly abundant source of Monumental Timber with numerous uses in monument, temple, or ship construction in Antiquity and Exploration Ages.
The loess hills of China provided a source for very fine wind-blown soil which also had a metal content, so made the perfect raw material for Porcelain once they had kilns hot enough - and Porcelain was a major Luxury and trade item for centuries and a major Unique Bonus for China.
The Black Hills provide a 'rain shadow' which results in extremely lush and rich grazing grounds for all kinds of herded and hunted beasts. Thus, a major source of Resources in Antiquity. That abundance also gave them Religious significance - it's why the Lakota called them "The Heart of Everything That Is."
Point is, neither the loess hills nor the Black Hills are particularly distinctive graphically (unless you carve some presidents on them), so they are not great candidates for Natural Wonders, But, they could be candidates for Special Resources - add a little flair of extra graphic interest to otherwise non-noteworthy tiles, and either more or unique Resource to the gamer.
The fact that exactly what kind of Special resource you get would be almost completely random (unless you are playing a TSL game) should make those Resources not game-changing, but simply game-improving or 'nice to have' except in extreme situations - as, IRL, the Cedars being virtually the only Monumental Timber within reach for many of the Mediterranean/Middle Eastern states of Antiquity, which dramatically increased their importance as a Trade item to them.