As we move further into 2015, we see a new 9th megatrend emerging to shape the future of the City, in addition to the "Eight Megatrends: The Future of San Francisco" I discussed in previous editions -- and that is the huge scope of international investment here.

As highlighted in this fascinating study by Savills, San Francisco is now ranked 5th in the world for international investment in real estate, right behind the world's major financial capitals, and rapidly catching up. This is reflected in a new record high for the median home price in the City. It will be interesting to see what the ranking will be like by next year!

This leads to the next big question: when will the first $100,000,000 residential sale occur in San Francisco?

Most Expensive City Blocks in the US for Single Family Homes
Broadway Street in San Francisco - East 70th Street in New York

Having been asked recently about luxury real estate prices in San Francisco versus Manhattan, I did some research and found that for single family homes, there are three blocks in each city that can lay claim to the most expensive in the entire nation.

In San Francisco it's Pacific Height's Gold Coast, and in New York it's East 70th Street in Lenox Hill. But which area has the highest prices? Here is what I found!

Designer Reed Krakoff's Townhouse at 113-115 East 70th Sold For $51 Million
Photo: Douglas Friedman for Elle Decor

While Manhattan condo prices reach the $100 million level, with buyers clamoring for stunning views and the prestige of an ultra-luxe penthouse, the three blocks of East 70th Street running from 5th Avenue to Lexington are ideal for the buyer preferring a more traditional townhouse on a quiet, tree-lined street.

Bunny Mellon's NY Townhouse at 125 East 70th Sold for $41 Million

Often described as the best blocks in New York, there are less than 25 townhouses, and they all go for mega-sums (especially on the north side of the street.) Four have sold in the past year, ranging from $37 million to $51 million, and two are on the market now for $33 million (116 East 70th) and $40 million (41 East 70th.) 

116 East 70th is on the Market for $33 Million

Despite such high prices, there is one thing that no New York home can possibly provide at any price: a view of the San Francisco Bay! And that's where the Gold Coast comes in.

Golden Gate Views from Pacific Heights' Gold Coast
Running along Broadway from Divisadero to Lyon Street, there are roughly 40 houses clustered together to form the priciest neighborhood on the West Coast. The best have unobstructed views of the Bay -- a premium now worth $3500+ per square foot.

2701 Broadway Just Sold For $31 Million
Demand for a Gold Coast home is always lurking, but transactions are rare since owners never want to leave! Now for the numbers.

The highest sale in the neighborhood occurred for $35 million, and the beautiful home at 2701 Broadway just sold> for $31 million. What does that say for future sales on Broadway? Don't be surprised if the next major transaction is near $40 million, and in my estimation the very best properties are reaching a value at or above $100 million.

So in comparing San Francisco with New York, East 70th is pricier, but the Pacific Heights Gold Coast is not far behind. Bottom line: it will cost you a minimum of $30 million to live in either neighborhood (unless you find a smaller home that needs a lot of work), and the best of the best will have a nine figure price tag.

"Versailles in the Sky" for $50 Million, at 50 Central Park South, NY
While the current trend toward ultra-modern minimalism has become mainstream, classical architecture and design will always be in style!

Some of the world's most expensive real estate is inspired by the grandeur of French architecture, from a $50 million "Versailles in the Sky"condo  on Central Park South, to a Ukrainian billionaire's Upper East Side Versailles-inspired mansion for $27 million.

My Own "Versailles in the Sky" on Nob Hill, Back in 2006
Photo: Brandon Joseph Baker for SF Chronicle
On a personal, humorous note (as well as a somewhat smaller scale!), the term "Versailles in the Sky" was originally coined by Carolyne Zinko in 2006, describing my own Nob Hill penthouse at The Francesca when she profiled it in the San Francisco Chronicle as "Versace Meets Versailles- in the Sky!" which, by the way, is not currently for sale, LOL... 

Randi Zuckerberg's Los Altos Home, Asking $5.48 Million
In the Bay Area, we are seeing some wonderful properties go on the market this month, from one of the few examples of Neo-Classical architecture in Pacific Heights, to Randi Zuckerberg's delightful Georgian-style home in Los Altos, as well as this charming Calistoga garden estate with over 100 valley oaks, including one estimated to be 300-400 years old!

My Pacific Heights Listing for $12.5 Million
I'm particularly pleased to be listing a stunning ~10,000 square foot Georgian mansion in the Gold Coast neighborhood of Pacific Heights, designed in 1899 by renowned architect Edgar Matthews.

My Pacific Heights Listing for $12.5 Million
Featured in one of the most famous silent movies in 1924 starring Buster Keaton, this home retains the extraordinary architectural grandeur of another era combined with a timeless contemporary remodel for today's lifestyle -- truly a seamless blend of old and new.

My Potrero Hill Listing, Price Upon Request
Another exciting new listing of mine is a stunning modernistic residence on Potrero Hill with panoramic views of the Bay, Bridge and the Skyline, as well as a sensational cubist facade.

Dramatic Views from Potrero Hill
With the incredible tech, bio-tech and health-care boom going on in Mission Bay, this neighborhood is rapidly becoming one of the most strategically-located to access the world's leading technology centers in San Francisco and Silicon Valley.

We're Listing This Spanish Mediterranean Duplex in the Marina for $4.595 Million
As is reflective of this hot real estate market, it's been a super-busy month for my team with the exciting listing of one of the Marina's most iconic Spanish Mediterranean duplexes, and a grand Park Avenue style residence at The Francesca on Nob Hill.

My Listing at The Francesca on Nob Hill
We also have a unique 13 acre homesite with views of the Bay in the Pensinsula.

Rupert Murdoch's NY Penthouse for $72 Million
Outside of San Francisco, celebrity real estate has been on the move this month from the listing of Rupert Murdoch's New York penthouse, Carlos Slim's mansion for a record-breaking $80 million, Bravo TV host Stephen Collins' fabulous mid-century Palm Springs home, and here is an amusing  tongue-in-cheek glimpse into Frank Sinatra's former penthouse.

Stephen Collins' Palm Springs Home For $1.35 Million
We're also seeing a slew of properties around the world with a fascinating provenance. From this Grand Gothic Penthouse of Silver Screen fame to the "Western White House," the scene of historic political moments, and this Saudi Sheikh's Morrocan-style Taj penthouse at the Palace condominiums in Miami.

Zaha Hadid's Vision for Monterrey, Mexico
The wave of starchitect projects around the world continues with this undulating Manhattan tower by Sir Norman Foster, as well as his ocean liner-shaped train station in London; Zaha Hadid's massive apartment complex in Monterrey, Mexico inspired by pre-Columbian architecture; and a revived trend in global metropolises to create house-like residences in the sky. We also now have a rare peek inside the 2013 winner of the Best Tall Building Worldwide, the CCTV Headquarters in Beijing, by Rem Koolhaas, who will also be designing one of the newest skyscrapers coming to San Francisco.

We are also seeing innovative use of materials, such as this avant-garde copper-clad condo tower, and unusual forms and features, like this Miami high-rise with a impressive Waterfall Wall and dramatic sky bridge.

The Shanghai Tower is 2,073 Feet High!
The most dramatic new example of green building practices is the new 2,073 foot high Shanghai Tower featuring 10 acres of sky gardens 1,000 feet above street level!

But as bold as the Shanghai-rise may be, the most revolutionary development in environmental friendly engineering is Tesla's new solar-powered battery that has the potential to help homes go off the power grid completely!

Jaume Plensa Art Installation in Basilica of San Giorgio Maggiore
Around the world, the most iconic historic buildings are being completely reinvented and revived, as we see in the conversion of the gilded Crown building overlooking Central Park into condos, and the placement of an ultra-modern art installation in a 400-year old Venetian basilica. A neo-Renaissance-style Upper East side mansion of the Gilded Age is going into the modern age -- formerly home to the tony Crown restaurant, it is now being marketed as a potential gallery or private club, or back to being a private mansion.

Speaking of mixed-use buildings, I'm very excited about the prospect of the iconic Teatro Zinzanni doing a dinner theater, hotel and public park project along San Francisco's Embarcadero waterfront.  The Mexican Museum Tower will be a combination of museum, retail, restaurant and office on the lower floors and ultra-luxury condominiums above, and will also include the adjacent historic Aronson building.

And it's exciting to see the Giants huge new multi-use project at Mission Rock, with plans for 33% affordable housing.

Electric Fashion by Christine Suppes and Frederic Aranda
Meanwhile, I am honored this month to be supporting the Golden Gate Philharmonic, an inner city San Francisco Youth Orchestra, and attending a wonderful recital at the scenic Swedenborgian Church benefiting the organization. I'm also looking forward to the launch of San Francisco author Christine Suppes' book with photographer Frederic Aranda: "Electric Fashion," published by Skira Rizzoli.