Into the Unknown
The Bara Imambara in Lucknow, India, has a huge 18th century hall, which is one of the largest rooms in the world with a vaulted roof without any beams. It was built on marshy ground, so the huge walls and arches needed for the support could not be solid, and are hollow, with hundreds of arches and passageways within the walls and foundations. Almost inadvertently the builders created a massive maze, which formed a useful escape route for the royal family. Tourists are shown around the upper galleries, with many glimpses of the ornate rooms below, but the lower levels are too difficult to navigate and are out of bounds. Apparently a British explorer, who insisted he was up to the task, is still down there.
Interestingly this huge, ornate building was started by the local ruler during a famine to provide income for farmers who would otherwise have starved. He knew their pride would not allow them to simply take a gift of money. It is said that each night the nobility would knock down what had been built the previous day, thus prolonging the building work until the end of the famine.
The photo shows one of the galleries in the maze.
(I am on a rainy beach holiday with grandchildren at the moment, so had to find something stored on my phone. Only phone cameras were allowed in the Bara Imambara, so that is what I used. Pixel-peepers will be disappointed!)