He had one offer: Goldman Sachs.

**Sidney Weinberg mopped the floors at Goldman Sachs - but when markets collapsed, the fate of the entire firm rested on his one secret ability…** At 16, Sidney Weinberg rode the elevator to the top of the largest building in New York, stuck his head in every office and said: “Want a boy?”. He had one offer: Goldman Sachs. The firm hired him as Assistant Janitor for $3 a week. His duties? Scrub the floors. Polish partners’ shoes. Clean their spittoons. Brush their hats before they walked onto Wall Street. But while crouched on the floor polishing shoes, Sidney overheard deals, memorised names and studied exactly how the firm’s leaders moved and spoke. Paul Sachs - grandson of the founder - spotted his ambition, moved him to the mailroom, and paid for him to attend investment bank...