diff --git a/README.md b/README.md
index 7c3d36d..8f6814c 100644
--- a/README.md
+++ b/README.md
@@ -29,19 +29,30 @@ This is the website of the CCCB.
 
 Every change you make on the project will be reflected in your browser as long as `hugo serve` is running.
 
-The *"Nächste Veranstaltungen"* calendar on the home page is rendered by
-Hugo via the `calendar` shortcode, which fetches `all.ics` client-side.
-`all.ics` is generated from the individual event pages by `./tools/merge_cals.py`.
-To preview the fully-built site (including `all.ics`), or to ready the site for
-upload, run:
+The *"Nächste Veranstaltungen"* table on the home page and the calendar under `/verein/calendar/` are rendered in the
+browser by `assets/js/upcoming.js` and `assets/js/calendar.js`. Both fetch `/calendars/all.ics`, which is **not**
+generated by Hugo and is not part of this repo — it is published separately on the web server. Without it both tables
+stay empty. Download the published calendar into `static/`, which Hugo serves under the same path, and they work
+locally, under `hugo serve` as well as in a built site:
+
+```shell
+mkdir -p static/calendars
+curl -o static/calendars/all.ics https://berlin.ccc.de/calendars/all.ics
+```
+
+The file is only there to look at the site, it is not checked in. Download it again whenever you want the events that
+are currently published.
+
+Hugo does generate an `.ics` feed per section (for example `/veranstaltungen/index.ics`) from the `dtstart`, `dtend`
+and `rrule` front matter of the pages in `content/veranstaltungen/`, using the `.ics` templates under `layouts/`.
+
+To build the site for upload, run:
 
 ```shell
 ./build.sh
 ```
 
-`build.sh` runs `hugo`, generates `all.ics`, and copies it into `public/`.
-It depends on Python with the `icalendar`, `python-dateutil`, and `pytz`
-packages. Inside `nix develop` these are provided automatically.
+This deletes `public/` and runs `hugo` with the parameters from `.hugo-params`.
 
 To build with *nix*: `nix build '.?submodules=1#production-content'`
 
diff --git a/build.sh b/build.sh
index d2b3eb3..625a262 100755
--- a/build.sh
+++ b/build.sh
@@ -5,5 +5,3 @@ set -ex
 rm -rf public/ # delete old generated files
 
 hugo $(cat .hugo-params)
-./tools/merge_cals.py
-cp static/all.ics public/all.ics
diff --git a/dev.sh b/dev.sh
index 9cbb013..2db7841 100755
--- a/dev.sh
+++ b/dev.sh
@@ -2,9 +2,6 @@
 
 set -e
 
-# Regenerate the merged calendar so the JS calendar widget has fresh data
-./tools/merge_cals.py 2>/dev/null || echo "Note: merge_cals.py skipped (no public/ dir yet)"
-
 hugo server \
     --buildDrafts \
     --buildFuture \
diff --git a/flake.nix b/flake.nix
index 386f9db..c29b73a 100644
--- a/flake.nix
+++ b/flake.nix
@@ -58,9 +58,6 @@
           buildPhase = ''
             mkdir -p public
             hugo --baseURL=https://${domain}/
-
-            python3 ./tools/merge_cals.py
-            cp static/all.ics public/all.ics
           '';
 
           # Install phase - copy the public directory to the output