Utilize the input text as a context reference, choose the right relationship between apartment and London from the options. Options: product/material produced, manufacturer, distributed by, industry, position held, original broadcaster, owned by, founded by, distribution format, headquarters location, stock exchange, currency, parent organization, chief executive officer, director/manager, owner of, operator, member of, employer, chairperson, platform, subsidiary, legal form, publisher, developer, brand, business division, location of formation, creator.

From my notepad: one leg of Viking Star's maiden voyage May 12: Tube from north London apartment to Greenwich wharf (about 30 minutes from King's Cross) and board Viking Star for the five-day cruise from London to Bergen.

Answer: location_of_formation