diff --git a/src/datomish/places/import.cljc b/src/datomish/places/import.cljc
new file mode 100644
index 00000000..3c3c5123
--- /dev/null
+++ b/src/datomish/places/import.cljc
@@ -0,0 +1,74 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(ns datomish.places.import
+  #?(:cljs
+     (:require-macros
+      [datomish.pair-chan :refer [go-pair <?]]
+      [cljs.core.async.macros :refer [go]]))
+  (:require
+   [datomish.util :as util #?(:cljs :refer-macros :clj :refer) [raise raise-str cond-let]]
+   [datomish.sqlite :as s]
+   [datomish.api :as d]
+   #?@(:clj [[datomish.pair-chan :refer [go-pair <?]]
+             [clojure.core.async :as a :refer [chan go <! >!]]])
+   #?@(:cljs [[datomish.pair-chan]
+              [cljs.core.async :as a :refer [chan <! >!]]])))
+
+(def places-schema-fragment
+  [{:db/id        (d/id-literal :db.part/user)
+    :db/ident     :page/url
+    :db/unique    :db.unique/identity
+    :db/valueType :db.type/string ;; TODO: uri
+    :db.install/_attribute :db.part/db}
+   {:db/id        (d/id-literal :db.part/user)
+    :db/ident     :page/guid
+    :db/unique    :db.unique/identity
+    :db/valueType :db.type/string ;; TODO: uuid or guid?
+    :db.install/_attribute :db.part/db}
+   {:db/id          (d/id-literal :db.part/user)
+    :db/ident       :page/title
+    :db/cardinality :db.cardinality/one
+    :db/valueType   :db.type/string
+    :db.install/_attribute :db.part/db}
+   {:db/id        (d/id-literal :db.part/user)
+    :db/ident     :page/visitAt
+    :db/cardinality :db.cardinality/many
+    :db/valueType :db.type/long ;; TODO: instant
+    :db.install/_attribute :db.part/db}
+   ])
+
+(defn- place->entity [[id rows]]
+  (let [title (:title (first (filter :page/title rows)))]
+    (cond-> {:db/id (d/id-literal :db.part/user)
+             :page/url (:url (first rows))
+             :page/guid (:guid (first rows))
+             :page/visitAt (map :visit_date rows)}
+      title (assoc :page/title title))))
+
+(defn import-places [conn places-connection]
+  (go-pair
+    ;; Ensure schema fragment is in place, even though it may cost a (mostly empty) transaction.
+    (<? (d/<transact! conn places-schema-fragment))
+
+    (->>
+      ["SELECT DISTINCT p.id, p.url, p.title, p.visit_count, p.last_visit_date, p.guid,"
+       "hv.visit_date"
+       "FROM moz_places AS p LEFT JOIN moz_historyvisits AS hv"
+       "WHERE p.hidden = 0 AND p.id = hv.place_id"
+       "ORDER BY p.id, hv.visit_date"
+       "LIMIT 20000"] ;; TODO: remove limit.
+      (interpose " ")
+      (apply str)
+      (vector)
+
+      (s/all-rows places-connection)
+      (<?)
+
+      (group-by :id)
+
+      (map place->entity)
+
+      (d/<transact! conn)
+      (<?))))
diff --git a/src/datomish/util.cljc b/src/datomish/util.cljc
index aa9c205e..31e25bb6 100644
--- a/src/datomish/util.cljc
+++ b/src/datomish/util.cljc
@@ -70,3 +70,5 @@
            (f (first xs) (first ys))
            (recur f (rest xs) (rest ys)))))
 
+(defn mapvals [f m]
+  (into (empty m) (map #(vector (first %) (f (second %))) m)))
diff --git a/test/datomish/db_test.cljc b/test/datomish/db_test.cljc
index 8f875dcd..532a8170 100644
--- a/test/datomish/db_test.cljc
+++ b/test/datomish/db_test.cljc
@@ -15,12 +15,14 @@
    [datomish.sqlite :as s]
    [datomish.sqlite-schema]
    [datomish.datom]
-   #?@(:clj [[datomish.pair-chan :refer [go-pair <?]]
+   #?@(:clj [[datomish.jdbc-sqlite]
+             [datomish.pair-chan :refer [go-pair <?]]
              [tempfile.core :refer [tempfile with-tempfile]]
              [datomish.test-macros :refer [deftest-async]]
              [clojure.test :as t :refer [is are deftest testing]]
              [clojure.core.async :refer [go <! >!]]])
-   #?@(:cljs [[datomish.pair-chan]
+   #?@(:cljs [[datomish.promise-sqlite]
+              [datomish.pair-chan]
               [datomish.test-macros :refer-macros [deftest-async]]
               [datomish.node-tempfile :refer [tempfile]]
               [cljs.test :as t :refer-macros [is are deftest testing async]]
diff --git a/test/datomish/places/import_test.cljc b/test/datomish/places/import_test.cljc
new file mode 100644
index 00000000..4ade271c
--- /dev/null
+++ b/test/datomish/places/import_test.cljc
@@ -0,0 +1,79 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+(ns datomish.places.import-test
+  #?(:cljs
+     (:require-macros
+      [datomish.pair-chan :refer [go-pair <?]]
+      [datomish.node-tempfile-macros :refer [with-tempfile]]
+      [cljs.core.async.macros :as a :refer [go]]))
+  (:require
+   [taoensso.tufte :as tufte
+    #?(:cljs :refer-macros :clj :refer) [defnp p profiled profile]]
+   [datomish.api :as d]
+   [datomish.places.import :as pi]
+   [datomish.util :as util #?(:cljs :refer-macros :clj :refer) [raise cond-let]]
+   [datomish.sqlite :as s]
+   #?@(:clj [[datomish.jdbc-sqlite]
+             [datomish.pair-chan :refer [go-pair <?]]
+             [tempfile.core :refer [tempfile with-tempfile]]
+             [datomish.test-macros :refer [deftest-async]]
+             [clojure.test :as t :refer [is are deftest testing]]
+             [clojure.core.async :refer [go <! >!]]])
+   #?@(:cljs [[datomish.promise-sqlite]
+              [datomish.pair-chan]
+              [datomish.test-macros :refer-macros [deftest-async]]
+              [datomish.node-tempfile :refer [tempfile]]
+              [cljs.test :as t :refer-macros [is are deftest testing async]]
+              [cljs.core.async :as a :refer [<! >!]]])))
+
+#?(:cljs
+   (def Throwable js/Error))
+
+(tufte/add-basic-println-handler! {})
+
+(deftest-async test-import
+  (with-tempfile [t (tempfile)]
+    (let [places (<? (s/<sqlite-connection "/tmp/places.sqlite"))
+          conn (<? (d/<connect t))]
+      (try
+        (let [report    (profile {:dynamic? true} (<? (pi/import-places conn places)))]
+
+          (is (= nil (count (:tx-data report)))))
+        (finally
+          (<? (d/<close conn)))))))
+
+(deftest-async test-import-repeat
+  ;; Repeated import is worst possible for the big joins to find datoms that already exist, because
+  ;; *every* datom added in the first import will match in the second.
+  (with-tempfile [t (tempfile)]
+    (let [places (<? (s/<sqlite-connection "/tmp/places.sqlite"))
+          conn (<? (d/<connect t))]
+      (try
+        (let [report0   (<? (pi/import-places conn places))
+              report    (profile {:dynamic? true} (<? (pi/import-places conn places)))]
+
+          (is (= nil (count (:tx-data report)))))
+
+        (finally
+          (<? (d/<close conn)))))))
+
+#_
+(defn <?? [pair-chan]
+  (datomish.pair-chan/consume-pair (clojure.core.async/<!! pair-chan)))
+
+#_ [
+    (def places (<?? (s/<sqlite-connection "/tmp/places.sqlite")))
+    (def conn (<?? (d/<connect "/tmp/testkb.sqlite")))
+    (def tx0 (:tx (<?? (d/<transact! conn places-schema-fragment))))
+
+    (tufte/add-basic-println-handler! {})
+    (def report (profile {:dynamic? true} (<?? (pi/import conn places))))
+
+    ;; Empty:
+    ;; "Elapsed time: 5451.610551 msecs"
+    ;; Reimport:
+    ;; "Elapsed time: 25600.358881 msecs"
+
+    ]
diff --git a/test/datomish/test.cljs b/test/datomish/test.cljs
index 0800a06b..10070500 100644
--- a/test/datomish/test.cljs
+++ b/test/datomish/test.cljs
@@ -2,6 +2,7 @@
   (:require
    [doo.runner :refer-macros [doo-tests doo-all-tests]]
    [cljs.test :as t :refer-macros [is are deftest testing]]
+   datomish.places.import-test
    datomish.promise-sqlite-test
    datomish.db-test
    datomish.query-test
@@ -12,6 +13,7 @@
    datomish.test-macros-test))
 
 (doo-tests
+  'datomish.places.import-test
   'datomish.promise-sqlite-test
   'datomish.db-test
   'datomish.query-test