KING 5 fielded a lot of questions and comments on why a historic mansion on sale for $15 million pays no property tax.

We first told you about the Sam Hill home Wednesday, and now the city is explaining why it granted this "special tax valuation." We also found which other buildings are getting the same deal.

"They tell us a story about our past," said Genna Nashem with the city's Historic Preservation office.

The Sam Hill home hit the market last week with a $15 million price tag creating a buzz in real estate circles. Perhaps the most stunning feature is its property tax of $0.

The city calls the "special tax valuation" an incentive.

It allows the city "to be able to give an incentive to be able to maintain historic properties across Washington state," said Nashem.

People sounded off on our Facebook page:

"1 percenters taking advantage of every loophole" wrote one viewer.

Historic landmarks get the tax break if the renovations to the property are more than 25 percent of the assessed value.

70 buildings in the city qualify according to the Assessor's office. Other million dollar landmarks with zero taxable value are the Masin's building in Pioneer Square, the Milwaukee Hotel in the International District, and MOHAI on South Lake Union.

Photos: Other Seattle homes that don't pay property taxes

Most are for business or public use. So why does a private residence like the Sam Hill home get the exemption?

"The law that was developed that allows the special tax valuation, doesn't make a differentiation if it's a private property or public property," said Nashem.

We found one other home on Summit Avenue that is on the list. It sits just blocks away from the Sam Hill mansion.

That's because the city designated the entire neighborhood, the Harvard-Belmont district, to be a preservation landmark. If any of the homes here spent enough in renovations, they too would get the "special tax valuation."

The city explains the founders of Seattle built their homes here.

"They're not museums but they're educational tools for us to learn from our city's past," said Nashem.

Publicly accessible? Perhaps not, but visible from the public right away.