I bought a (rather large) condo in 2015 for just shy of $600k. In 2017, the same unit in my building on another floor sold for over $900k. 50% increase in value

I bought a (rather large) condo in 2015 for just shy of $600k. In 2017, the same unit in my building on another floor sold for over $900k. 50% increase in value while we did nothing. That's not normal. That's a bubble. That said, the prices haven't gone up in 3 years now- no one is getting $900k for this unit anymore.