Crimea for Russia as an example, but this is also true for other former Soviet states.
With China it's been Bhutan, India, Vietnam, Philippines, Malaysia, Brunei, Indonesia and Japan. In addition to their claims over Taiwan or their excuse to (culturally) genocide the Uighur in China).
That is ignoring Africa as a whole, where conflicts are far more common. To name a recent example, over 50,000 Nigerian Christians have been killed by Islamists in the past 16 years. The world is far more bloody than most people seem to realize. The world peace has only been a peace in a relative sense.