Although the fortress-like exterior of this 1873 building is pretty impressive, it's the spectacular interiors – which took a further 15 years to complete – that really blow visitors away. Fans of secret societies and theatrical design will be in raptures as each meeting room sports an astonishingly detailed theme – Moorish, Egyptian, Renaissance and more.

　　Freemasonry's roots in the city stretch back to colonial times – in the library, where tours of the building start and finish, you can view George Washington's masonic apron. Most of the mural paintings and primary designs are by German immigrant George Herzog. This was also one of the first buildings in the city to be lighted by electricity.