According to the fourth quarter 2015 RLB Crane Index, 220 cranes currently dot the Sydney skyline. A whopping 170 of these cranes were devoted to residential projects, some of which will become the tallest buildings in the city. The rate of growth shows no real signs of slowing down either; new development applications lodged with City Hall totalled $7.4 billion AUD worth of investment. With its urban makeup constantly changing, we take a look at some of the largest towers planned for Australia's biggest metropolis.

Sydney Crown, image via Wilkinson Eyre

Located on the northwestern edge of Sydney's central business district (CBD), Barangaroo is a former port facility undergoing a massive transition into a bustling mixed-use neighbourhood. The $6 billion AUD waterfront redevelopment is being managed by the Barangaroo Delivery Authority on land owned by the New South Wales government. The parcel has been split into three distinct areas: Barangaroo Reserve, Central Barangaroo, and Barangaroo South. Acting as an extension of the CBD, the Lendlease-developed Barangaroo South will include a number of tall skyscrapers, including the 271-metre Sydney Crown.

Sydney Crown, image via Wilkinson Eyre

Designed by Wilkinson Eyre, the 70-storey hotel and casino complex will include 350 guest rooms plus luxury apartments and retail. As the first six-star international hotel to be constructed in Sydney, it will finally surpass the Chifley Tower as the tallest building in the city, a record the 53-storey tower has held since 1992.

One Sydney Harbour, image via Renzo Piano Building Workshop

Within the same precinct, Renzo Piano Building Workshop promises to bring two residential towers to life. One Sydney Harbour's 71- and 60-storey glass towers are the last pieces of the puzzle to come together. A trio of office towers designed by Rogers Stirk Harbour + Partners, the International Towers, will also join the emerging waterfront skyline. Construction on those three buildings has already begun, and the entire Barangaroo South district is scheduled for completion in 2021.

International Towers, image via Rogers Stirk Harbour + Partners

Though Sydney Crown appears locked in to become the tallest skyscraper in the city, the 78-storey 505 George Street will top out at a height just nine metres shorter. Developed by Coombes Property Group and Mirvac, who have hired Crone Architects, the project will contain 629 residential units and over 10,000 square feet of retail.

505 George Street, image via Crone Architects

In addition to world-famous architects making their mark on the city, major international developers are also investing in the country. China's largest real estate developer, Greenland Group, unveiled plans to build a 245-metre building with 66 floors. The Sydney Greenland Centre features a design by BVN Donovan Hill and Woods Bagot, who have proposed a rectangular glass tower atop the existing Art Deco Metropolitan Water Sewerage and Drainage Board building. That building is being converted into a 180-bed hotel which is due for completion in 2016. The residential tower will forgo any floor numbers with "four" in them, as the number has a similar pronunciation to "death" in Mandarin. The tower is being marketed as a 82-storey building as a result. Now under construction, completion of the full project is expected in 2019.

Sydney Greenland Centre, image via Woods Bagot

Several of the towers listed above exceed Sydney's longstanding height limit of 235 metres. After 40 years, there is increasing pressure to raise the limit so that more growth can be accommodated in the central core. Technically, developers can build up to 257 metres, though they would have to sacrifice ten percent of floor space to do so. That is putting a strain on developers hoping to add more office space and residential units to the city. New South Wales Premier Mike Baird is hoping to lift the restriction, pointing to other cities like Melbourne who are building towers exceeding the supertall mark.

Additional images and information on the projects above can be found in the Database files linked below. Want to get involved in the discussion? Check out the associated Forum threads or leave a comment at the bottom of this page.