Washington, D.C., has been called one of the most masterfully planned-out cities in the world.

But there are a lot of ideas for the District that never quite made it off the drawing board.

The Washington Monument could have been a pyramid. The Capitol building might have been home to the president. And, if famed architect Frank Lloyd Wright had his way, the current site of the Washington Hilton would be home to shops, restaurants, a movie theater and even a cabaret.

How Washington came to be — and what it didn’t come to be — is studied in detail in “Capital Drawings,” a new book that looks at the architectural designs that shaped the city.

“It makes you think about how important architecture and design is in our lives,” said C. Ford Peatross, the book’s editor and curator of architecture, design and engineering collections at the Library of Congress. “Washington is where we act out our great celebrations as a nation. It’s where we mourn communally. It’s where new ideas are tested. In that sense, it’s a barometer of where we are as a people.”

The LOC will celebrate the publication today at 6:30 p.m. in Madison Hall. It spent 10 years cataloging more than 40,000 drawings, prints and photographs detailing the architectural creation of the city.

The book is “a very practical portal to our collections,” Peatross said.

Through design proposals, sketches and essays, the book studies the design process of the Capitol, White House, Vietnam Veterans Memorial and the city’s commercial and residential core. It also looks at the detailed way Washington’s original designers laid out their plans for the nation’s capital.

“It’s bringing attention to some of the geniuses,” Peatross said. “We were so lucky that we had these incredibly intelligent, bright architects.”

Perhaps one of the more interesting aspects of the book comes from Peatross’ Chapter 1 essay, which highlights many of the designs that didn’t end up happening.

There are some that seem a little crazy, such as the proposal for a hotel where guests could swim with dolphins. Or another hotel design that featured a dual swimming pool and movie theater.

And then there is Crystal Heights, proposed by Wright. The complex would have had a hotel, shops, apartments, restaurants and other entertainment venues, surrounded by fountains and marble towers.

“It would have been spectacular,” Peatross said.

Some went-nowhere ideas might have made the city a better place, Peatross said. Proposals for the District’s southwest waterfront would have allowed for an incredible view of the Capitol and created a vibrant economic marketplace.

And in some of the original designs for the Capitol, there is an area for a conference room that might have made the art of creating legislation a bit easier.

“It presumably would have been neutral ground where the House and Senate would have worked out their differences,” Peatross said.

The president could have given his State of the Union address in that room, Peatross said. Or, the chief executive could have had offices there.

Peatross said he hopes readers will see the basic principals of how architects designed the city from the book.

“I hope lawmakers will, too, because they play an enormous role in the history of architecture,” Peatross said.

But he promises “Capital Drawings” won’t read like a textbook.

“It may be the first time ever a research guide is sexy,” Peatross said.

“Capital Drawings: Architectural Designs for Washington, D.C., from the Library of Congress” is published by The Johns Hopkins University Press. Retail cost for the book is $55.