Trump's ballroom costs are rising. What we know about the secret underground bunker

The development costs of President Trump's White House ballroom keep rising — as does speculation about what the finished project, including its underground complex, will look like.

The big picture: Trump 's ballroom project is more than a simple remodel of the East Wing.

It's a complete overhaul featuring what appears to be a military-grade underground bunker, meant to protect and secure the president.

The project remains in legal limbo after a federal appeals court ruled in August that Trump's ballroom plans need congressional approval.

Trump said he plans to ask the Supreme Court to overturn the decision.

By the numbers: The ballroom is expected to cost around $600 million — with about half of that coming from taxpayer dollars, The Washington Post reported.

It's an increase from the White House's initial $200 million estimate, which they said would come from private donors.

That amount was later amended to $400 million and then $600 million.

Trump's administration is also planning to spend at least an additional $300 million on other projects around the White House complex, including a helipad, a visitor screening center and changes to the Rose Garden, the Post reported.

In May, the Trump administration reportedly suggested asking taxpayers for $1 billion for security upgrades across the entire White House campus, though lawmakers seemed unconvinced by the request.

Reality check: Specifics about the ballroom and its underground complex remain unclear, as many of the details remain classified.

Trump himself has pointed to the "massive complex" being built underneath the ballroom.

Read what we know below.

What we know about the underground bunker Architect Shalom Baranes presents plans for President Trump's proposed White House ballroom to the National Capital Planning Commission in Washington, D.C., on Jan.