Despite it’s bounce back from the recession, the housing market has a new issue: It can’t keep up with the demand of potential home buyers.

Nearly half (47%) of homes on the market today sold in less than a month, according to the National Association of Relators. But with that kind of demand, there’s just not enough homes on the market to keep up.

“It’s an inventory issue that is really holding the market back,” says Charlie Young, CEO of Coldwell Banker, in an interview with Fortune live host Leigh Gallagher.

And that demand is expected to only increase, according to Young, as more first time home buyers are starting to come back into the market (before, the post recession housing market was fueled by luxury home sales, but that sector of the market is becoming more normalized, he says).

As for where the most expensive markets are? Buyers should look to California, but more specifically, Silicon Valley. According to the 2016 Coldwell Banker Home Listing’s report, which compares average four-bedroom homes in in 2,1000 markets around the country, California boasted the priciest homes, with the average home listing for over $2 million.

But thanks to Millennials, who are a large majority of the new age of buying consumers, cities like Detroit, Mich., are seeing a comeback. An average home there is a modest $64,000, Young says. He adds that less expensive homes on the market can also be found in the Midwest and South.

For their full conversation, please watch the video at the top of this post.