London has many world class architecture buildings, and many of them open its private door to public at Open House day, and allow general public to visit and enjoy the beauty of design, architecture, and rich history. Luckily this year when I walked through St. James Palace I saw people queued, or lined up in American English, next to this building. I joined the waiting list and enjoyed the surprise moment inside.
Short history, Lancaster House is used for many filming locations, government meeting and events, auction sale events, it was used as Buckingham Palace in quite few film and television programs.
Next time when you come to London, please come to have a look.
Main Hall
Ceiling Painting
Interior Decoration
American Eagle Room
Banquet Room
Painting Room
Chair
Inside Secret Room via an Door Hidden as a Wall