MASON CITY — California billionaire and Democratic presidential candidate Tom Steyer wrapped up a two-day swing through north-central Iowa on Monday. Steyer unveiled details of his affordable housing plan which would invest more than $625 billion over ten years in existing housing programs, create three-and-a-half million units of affordable housing, and mobilize an additional $600 billion to foster climate-smart cities and affordable housing.Steyer says housing is at the heart of inequality in the United States. “So many things depend on where you put your head down at night, and I think that solving and addressing this housing shortage and this housing crisis is something that’s critical addressing inequality around the country.”Steyer says there’s no state in the US where a minimum-wage worker can afford a market-rate two-bedroom apartment. “I announced it in Iowa because Des Moines has gentrification problems like the gentrification problems across this country. I’ve been to Council Bluffs to see the flooding, I know that they’re the issues about rebuilding houses, and I know there is enough housing stock in rural America.”Steyer says leaders at the local, state and federal level need to show leadership in addressing housing issues. We’re going to have to deal with our homelessness problem across the country explicitly. We’re going to have to help people to the traditional American wealth generation through home ownership, we’re going to explicitly have to help people along with that because that has gotten to be very problematic and particularly in red-lined areas. Lastly, we’re going to have to build climate-smart communities.” Steyer made stops in Mason City and Osage on Sunday, and Charles City and Northwood on Monday.