maps-geo
OldMapsOnline
A portal for discovering georeferenced historical maps held by institutions around the world, pointing you to the collection that holds each map. It offers a geographic (bounding-box) search API and IIIF endpoints, but we surface it as a link to its own search form. Currently flagged as degraded: the site may present a CAPTCHA before letting you in.
Cultural heritage captcha degraded
Search this archive
No programmatic check — opens the archive’s own search.
Why it’s useful & how it works
Niche/link-catalogue tier (see product-concept): surfaced as a described link to its search form. Probe verdict recorded for liveness.
API access
geo-search API by bbox; IIIF
Access
May require solving a captcha before it responds.