US ambassador to the United Kingdom Robert “Woody” Johnson showed media around the new US embassy in London on Wednesday.

Slated to open on 16 January, the new 12-storey glass embassy cost $1 billion - the most expensive embassy ever built.

It's been described as a crystalline “sugar cube” and a “modernist museum” that expresses openness and transparency - a far cry from the old fortress-like embassy that embodies a brutalist architectural design, according to the The Washington Post.

But make no mistake - the new embassy is highly secure and, as CBS notes, has been described as an “urban fortress.”

Take a look inside:

This is the US' new embassy in London. Seated on the banks of the River Thames, it cost $1 billion and will open 16 January

(Reuters (Reuters)

The new embassy is a 12-storey glass cube without visible walls, which the designer, James Timberlake, said he wanted to exude “transparency, openness, equality.”

Timberlake also said he was inspired by European castles - and there's even a moat.

The embassy rests on a hill about 100 feet back from the street, and the moat has waterfalls and deep trenches that could stop a truck bomb. It's even beset by a six-inch blast wall, which adds to the large price tag.

The building will also produce more energy than it uses: the roof is filled with solar panels, and the white part of the exterior is a plastic polymer that increases it's energy efficiency.

Here is the lobby entrance, which is adorned with the US State Department embossed seal and the names of every US ambassador to the United Kingdom

(AP) (AP Photo)

According to the Post, the inside is adorned with “frosted- glass walkways, inspirational quotes from the Constitution, neon sculptures, reclaimed teak benches, Cornwall granite, [and] its own subterranean wastewater treatment plan.”

The Evening Standard even called the inside of the embassy “stunning.”

In the consular section of the embassy is a huge photograph of the Winfield House garden, the official residence of the US ambassador to the UK

(Reuters (Reuters)

The plastic polymer veil offers a view from the inside out

(Reuters (Reuters)

There are also a dozen gardens in the embassy

(Reuters (Reuters)

Above is the Canyonlands Garden, which represents the Grand Canyon and the south west desert landscapes of the US.

The embassy also has a bar

(Reuters (Reuters)

It even has a gym, post office, Marine barracks, and probably a CIA station.