Thomas Jefferson’s “sanctum sanctorum” was where he read books in six different languages, corresponded with hundreds of people around the globe, puzzled over scientific mysteries and relaxed in solitude. With his greenhouse right outside and huge windows to let in sunlight, the space offered him a quiet retreat in an often bustling home to think, write and reflect. Now, when visitors come to Monticello and walk through the third president’s private quarters, they will see what Jefferson saw — a neatly arranged mix of carefully collected curiosities, books, papers and scientific instruments.