diff --git a/Cargo.lock b/Cargo.lock
index d02a685..d5c8d2b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -404,6 +404,18 @@ dependencies = [
  "inout",
 ]
 
+[[package]]
+name = "cities-json"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d4720186a8069da0585af9ec1e2f9e815d7d1bbe47dc817b8597e31a609f898f"
+dependencies = [
+ "lazy_static",
+ "rand 0.8.5",
+ "serde",
+ "serde_json",
+]
+
 [[package]]
 name = "clap"
 version = "4.3.17"
@@ -2266,6 +2278,7 @@ dependencies = [
  "chashmap",
  "chrono",
  "chrono-tz",
+ "cities-json",
  "clap",
  "config",
  "geo",
diff --git a/rtz-build/Cargo.toml b/rtz-build/Cargo.toml
index 79844be..ac996c4 100644
--- a/rtz-build/Cargo.toml
+++ b/rtz-build/Cargo.toml
@@ -13,10 +13,10 @@ categories = ["command-line-utilities"]
 
 [features]
 default = []
-full = ["tz-ned", "tz-osm", "admin-osm", "self-contained"]
+full = ["tz-ned", "tz-osm", "admin-osm", "self-contained", "rtz-core/full"]
 
 force-rebuild = []
-self-contained = []
+self-contained = ["rtz-core/self-contained"]
 
 tz-ned = []
 tz-osm = []
diff --git a/rtz/Cargo.toml b/rtz/Cargo.toml
index e9b6b7c..722c943 100644
--- a/rtz/Cargo.toml
+++ b/rtz/Cargo.toml
@@ -85,6 +85,7 @@ js-sys = { version = "0.3.61", optional = true }
 
 [dev-dependencies]
 pretty_assertions = "1.4.0"
+cities-json = "*"
 
 [build-dependencies]
 rtz-build = { path = "../rtz-build", version = "0.2.6"}
diff --git a/rtz/src/geo/tz/ned.rs b/rtz/src/geo/tz/ned.rs
index 3f01dfe..1b75136 100644
--- a/rtz/src/geo/tz/ned.rs
+++ b/rtz/src/geo/tz/ned.rs
@@ -224,4 +224,12 @@ mod bench {
             black_box(NedTimezone::lookup(x, y));
         });
     }
+
+    #[bench]
+    fn bench_cities(b: &mut Bencher) {
+        b.iter(|| {
+            let city = cities_json::get_random_cities();
+            black_box(NedTimezone::lookup(city.lng as f32, city.lat as f32));
+        });
+    }
 }
diff --git a/rtz/src/geo/tz/osm.rs b/rtz/src/geo/tz/osm.rs
index 7da56d0..8e4ebb5 100644
--- a/rtz/src/geo/tz/osm.rs
+++ b/rtz/src/geo/tz/osm.rs
@@ -230,4 +230,12 @@ mod bench {
             black_box(OsmTimezone::lookup(x, y));
         });
     }
+
+    #[bench]
+    fn bench_cities(b: &mut Bencher) {
+        b.iter(|| {
+            let city = cities_json::get_random_cities();
+            black_box(OsmTimezone::lookup(city.lng as f32, city.lat as f32));
+        });
+    }
 }