Four of the five condos in the massive Beacon Hill building are asking $20,000,000 total. The units are on sale as an especially tantalizing multi-family—the Greek revival has the necessary approvals for 1,844 additional gross square feet and nine underground parking spaces—but they could also end up as one, big private residence.

The 7,500-square-foot Greek Revival has three bedrooms and nine bathrooms (six full). It is former commercial space for the Unitarian Universalist Association, which sold it and its neighbor at No. 7 in March 2014. It is asking $12,950,000 with a commitment from the developer to complete all exterior work. Small caveat: The townhouse is available as a shell for just $8,500,000.

The 4,110-square-foot 3-BR, 4.5-BA in the recently opened spire is asking a $12,500,000. That is more than $3,000 a square foot, an incredible sum for Boston. It includes two gas fireplaces and two valeted parking spaces.

Unit 2 is one of only six condos in the under-conversion 25 Beacon. The 4,015-square-foot 3-BR, 3-BA overlooking the Common wants $10,500,000.

This condo spreads over 4,318 square feet on the tower's 37th floor. It has four bedrooms, an incredible six full bathrooms, and wants $10,000,000.

This 5,410-square-foot maisonette runs over three floors and includes three bedrooms and three and a half bathrooms. There's also a patio and a roof deck. The tag? $9,995,000.

This 4,132-square-foot condo in the recently converted building includes four bedrooms and a four and a half bathrooms. Two parking spaces come with the $9,495,000 price.

This 3,573-square-foot spread asking $9,100,225 is part of the Seaport's newest condo development. The spread includes three bedrooms and three and a half bathrooms.

The 3,577-square-foot 3-BR, 3.5-BA—one of only six units at the ongoing conversion—is asking $9,000,000 even.

This 2,770-square-foot unit unfolds over the entire second floor and includes three bedrooms as well as two and a half bathrooms. The asking price is $7,250,000 following steep cuts from $8,700,000 this summer.

Twenty Two Liberty is not even two years old, so Unit 12A is particularly shiny. It's a 2,756-square-foot 3-BR, 3.5-BA with a price tag of $7,195,000.

This 3,172-square-foot spread includes 28 floor-to-ceiling windows. The 3-BR, 4.5-BA wants $7,175,000.

The ongoing conversion of the old Holy Trinity German Catholic Church and rectory in the South End is one of Boston's more dramatic development projects. Unit 6 is the most expensive of its 33 units still available. The 5,295-square-foot 4-BR, 5.5-BA wants $6,750,000.

The 2,994-square-foot 3-BR, 4.5-BA condo is part of an ongoing conversion of an old Suffolk University building. The price is $6,500,000.

This 2-BR, 2.5-BA runs to 2,670 square feet and is asking $6,450,000.

This 3,198-square-foot 3-BR, 4.5-BA condo in the ongoing conversion wants $6,250,000.

This 3,704-square-foot 3-BR, 3.5-BA condo is part of a five-unit conversion of a Harvard Club property. The spread is asking $6,250,000.

The 2,864-square-foot 3-BR, 3.5-BA has 11-foot ceilings (the highest in the tower) and an asking price of $6,250,000.

The conversion of this apartment building into six luxury condos got underway in the fall. This 2,900-square-foot 3-BR, 2.5-BA is asking $5,950,000.