10 skyline-changing buildings under construction this year

U.S. cities are getting taller this year, thanks to a handful of new construction projects across the country.

The recession put dozens of major commercial and residential projects on hold, but with the economy coming back to life developers are eager to jump back on the building bandwagon.

In cities from coast to coast, skyline-altering projects will start growing this year. Philadelphia and San Francisco are preparing to build their tallest towers yet, while sprawling acres of corporate campuses will significantly change neighborhoods around Seattle and Phoenix. Even cities that haven't seen major downtown development in years will see their skylines change.

Take a look at 10 skyline-changing buildings under construction this year.

A new Comcast tower in Philadelphia

The Comcast Center will soon lose its title as Philadelphia's tallest building, bowing down to another company building, the Comcast Innovation and Technology Center. The cable and internet giant announced plans in January to build a $1.2 billion building, one story and about 150 feet taller than its current headquarters which it has outgrown in just five years. The new building, which breaks ground this summer, will include a Four Seasons Hotel and room for other tenants. It is expected to be finished in 2017.

It's not the only big project brewing in Philadelphia. A 47-story hotel and condo building along the city's Avenue of the Arts is also slated to begin construction this year.

Transbay Tower in San Francisco

Upon its completion in 2017, the Transbay Tower will become San Francisco's tallest building, soaring 1,070 feet off the ground. The 61-story, clear glass tower tapers until it reaches a transparent glass crown. At its base, a transit center will house 11 of the area's transit system lines, and on top of that, a 5.4-acre public park will act as an entrance to the building. Developers broke ground on the tower in March 2013 in the city's SoMa neighborhood.

Amazon’s dome headquarters in Seattle

Amazon’s new headquarters at Denny Triangle in Seattle will consist of three, 38-story high-rise towers, two mid-rise towers, a meeting center that seats 1,800 people and three glass greenhouse domes. The project encompasses 3.3 million square feet and three city blocks. It also includes a public dog park, cycle track and retail shops on the ground. Street work has begun with construction expected to continue until the project is completed in 2016.

State Farm’s office complex in Phoenix

State Farm Insurance's massive 2-million-square-foot regional headquarters may not rise into the clouds, but it will make a major impact on the skyline of Tempe, Ariz., where the tallest building is only 30 floors. The $600 million project, the largest office development in the state's history, consists of five buildings that vary from six to 17 stories and offer views of the University of Arizona's Sun Devil Stadium, Tempe Town Lake and Tempe Butte. The project, which will also offer space for retail, coffee shops and restaurants, broke ground over a former parking lot in July 2013 and is slated to be completed by late 2015. 

The New Wilshire Grand Hotel in LA

The New Wilshire Grand Hotel, which is being built on top of the 16-story former Wilshire Grand Hotel, is slated to be the tallest building west of the Mississippi River at 1,100 feet tall. Construction began just a few days ago with a Guinness World Records-setting overnight concrete-pouring session, complete with marching bands, parades and nearby bar specials. Estimated to cost nearly $1 billion, the Korean Air-developed project will feature a 900-room hotel and convention space, along with retail and office space when it opens in 2017.

Northwestern Mutual building in Milwaukee

Most of Milwaukee's tallest buildings went up in the 1980s, so not much has changed since then. However, a new building is about to join the pack. Work began last November on the 32-story headquarters for insurance firm Northwestern Mutual. The company is in the process of tearing down one of its old buildings -- leaving behind a message in lights that reads "Bye for now, See you in 17" -- to make way for the new $450 million tower near the city's lakefront and its iconic art museum. The company will expand its operation to fill the 550-foot building.

609 Main at Texas in Houston

Houston is booming with new oil and gas business and that means cranes are dotting its skyline now to help build the skyscrapers that will dot its skyline later. One of the tallest upcoming office buildings is a 41-story mixed-use tower in downtown Houston. Construction began on Nov. 1, even though the tower doesn't have any publicly-confirmed tenants. The building is set for completion in spring of 2017.

432 Park Avenue in NYC

New York City has quite a few buildings scheduled to reach new heights and 432 Park Avenue is one of note. When completed in 2015, the 1,400-foot-high building will become the tallest residential skyscraper in the western hemisphere. Occupying the site of the former Drake Hotel, along with adjoining spots on 56th and 57th Streets, the megatower will loom over nearby buildings. Living in the skyscraper will cost anywhere from $7 million to $95 million for a full-floor penthouse.

A handful of other Manhattan projects, including the 90-story One57 condo-hotel building, are slated for completion in 2014. That building will enjoy being the tallest residential building in New York until 432 Park Avenue is finished a year later. 

Millennium Tower in Boston

The 60-story Millennium Tower in Boston will offer 1.1 million square feet of residential and retail space, while an adjacent department store will be renovated to include office space. When completed in 2015, the tower will be the tallest residential building in Boston, featuring 450 luxury condominiums. The building has been in the planning stages since before the recession, but finally broke ground last September. 

Panorama Tower in Miami

This 830-foot residential building in Miami will offer apartments as well as retail, restaurants and meeting facilities. When this concrete tower is finished, it will not only be Miami's tallest tower, but the tallest in the state of Florida. However, it may soon be trumped by a proposed nearby tower, the Brickell CityCentre Front Door tower, which could top 1,000 feet, if the Federal Aviation Administration says it's ok. Construction is just getting underway and is expected to finish by 2016.