City audio tours are written by guides, and literary walking tours cover a few famous authors with hand-placed stops. Ghost Itinerary takes any public-domain travel diary, splits it into passages, and pins each one to the exact street where it was written about, with a confidence score. You walk today's streets and the traveller's own words unlock under your feet.
The data it runs on
Texts: public-domain travel diaries and letters from Project Gutenberg, Internet Archive and Wikisource. Thousands of 18th and 19th century accounts cover Naples, Cairo, Rome, Istanbul, Kyoto, Lagos, Calcutta and more.
Places: OpenStreetMap for today's streets and landmarks; Wikidata for historic names (P1448 official name with start and end dates); historical gazetteers such as the World Historical Gazetteer for old place names.
Access: texts are downloaded once and processed offline; place lookups use Nominatim and cached Wikidata queries.
Limits and gaps: many passages name a district, not a point; some streets were renamed or no longer exist; the writer's own attitudes are of their time and can be offensive.
Fallback: a passage that cannot be pinned plays when you enter its district (shown as a shaded circle), and a passage with no place at all goes into a "between places" reading at the end of the walk.
1. The mission
Let anyone walk a city beside someone who saw it 150 years ago. We turn forgotten public-domain diaries into living walks, honestly placed, so the past is something you can stand in.
2. Why people can't resist it
Presence. Hearing "I stood here" at the spot where you stand is uncanny and unforgettable.
Unlock by walking. The next passage is always one street away. People walk further than they planned.
Then and now. Seeing what vanished and what survived turns any street into a small mystery.
3. How it works for real
Ingest: clean the Gutenberg text, split by diary entry and paragraph.
Extract: a fast cheap model (Gemini Flash or DeepSeek via OpenRouter) tags place mentions, dates and directions ("turning left from the church").
Resolve: match each mention against old and new names in Wikidata and the gazetteer, then OSM for today's coordinates. A frontier LLM (Claude or GPT) adjudicates ambiguous cases and writes the reason.
Score: confidence combines name match quality, the diary's walking order, plausible distance from the last passage, and whether the landmark still exists.
Then and now: the LLM writes short cards from Wikipedia history sections, cited. Optional image model sketches of the past are labelled "illustration".
Narrate: TTS (ElevenLabs or OpenAI TTS) with an era-appropriate voice; geofences trigger playback on the phone.
4. Cost per use
One-time processing per diary, then near zero: about $2 to $6 to extract, resolve and narrate a whole book once; after that each walk only costs map tiles and cached audio.
Free: one traveller per city, text passages. Walker ($4 a month): every traveller, narration, offline walks and the full then-and-now archive.
5. Growth loop
People share the passage they heard at a spot ("a woman in 1873 stood exactly here"). Friends visiting the same city start the walk. Readers can nominate a diary, and volunteers confirm uncertain pins, which earns them credit on the walk.
Every Sunday a new armchair walk arrives, matched to the streets of your home city, and each one adds passages and a city to your My Walks atlas. The atlas only grows, so skipping a week leaves a visible gap.
6. Risks and guardrails
Old attitudes: passages with colonial or racist language carry a context note and are skippable; nothing is silently edited.
Copyright: only texts that are public domain in both the source and the user's country.
Honest placement: every pin shows its confidence; low-confidence passages show a shaded area, never a fake exact point.
Safety: audio-first walking, no prompts to stare at the screen while crossing roads.
7. MVP build order
Process one diary for one city by hand with an LLM extraction script, output passages as JSON with coordinates and confidence.
Map with route, pins and uncertainty circles.
Geofence unlock with simulated walk, then real GPS.