With waterfront properties running out in Miami, real estate developers are increasingly buying out the owners of existing and older waterfront condos at premium prices. After purchasing an entire building, developers are demolishing the old building to make space for a new luxury tower.

This is a process called condo termination — and while it’s complex, when it works, it can leave the owners of aging condos with an unexpected windfall and lead to a new property development.

And that’s precisely what happened at 175 SE 25th Road in Brickell. OKO Group spent a year negotiating individual sales of all of the 61 units on the previous property, paying a total of $48 million to buy the entire 11-story building in 2016. Fast forward, OXO Group, in partnership with Cain International, will turn the 25th Road site into Una, a 47-story luxury tower designed by Adrian Smith + Gordon Gill Architecture. The tower will hold 135 residences, each with a private elevator entry and prices will go from $900,000 to more than $5 million. Construction is slated to be completed by 2021.

Una is the latest example but not the first. Fortune International Group is currently developing a new project on the former site of the Playa de Varadero condo at 18801 Collins Ave., which was built in 1965. Other examples are the Residences by Casa/Armani in Sunny Isles Beach and the upcoming 17-story luxury condo at 5775 Collins Ave., which will be built on the site of the Marlborough House condo by Brazilian billionaire Jose Isaac Peres.