diff --git a/Package.swift b/Package.swift
index ad0e9bf..9e870b9 100644
--- a/Package.swift
+++ b/Package.swift
@@ -21,7 +21,8 @@ let package = Package(
         .target(name: "CZoneDetect"),
         .target(
             name: "SwiftTimeZoneLookup",
-            dependencies: ["CZoneDetect"]),
+            dependencies: ["CZoneDetect"],
+            resources: [.process("Resources")]),
         .testTarget(
             name: "SwiftTimeZoneLookupTests",
             dependencies: ["SwiftTimeZoneLookup"]),
diff --git a/README.md b/README.md
index d80ae25..0b61219 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,17 @@
 # SwiftTimeZoneLookup
 
 A description of this package.
+
+
+## Build database
+```bash
+brew install shapelib wget
+cd Submodules/ZoneDetect/database/builder
+
+# make sure to select to newest version in make.db script
+
+LIBRARY_PATH=/opt/homebrew/Cellar/shapelib/1.5.0/lib CPATH=/opt/homebrew/Cellar/shapelib/1.5.0/include ./makedb.sh
+
+cp out_v1/timezone* ../../../../Sources/SwiftTimeZoneLookup/Resources
+
+```
diff --git a/Sources/CZoneDetect/include/include.h b/Sources/CZoneDetect/include/include.h
index 83dc748..9d16941 100644
--- a/Sources/CZoneDetect/include/include.h
+++ b/Sources/CZoneDetect/include/include.h
@@ -1 +1 @@
-#include "../src/timezonedetect.h"
\ No newline at end of file
+#include "../src/zonedetect.h"
diff --git a/Sources/SwiftTimeZoneLookup/Resources/README.md b/Sources/SwiftTimeZoneLookup/Resources/README.md
new file mode 100644
index 0000000..f1c1d2f
--- /dev/null
+++ b/Sources/SwiftTimeZoneLookup/Resources/README.md
@@ -0,0 +1,5 @@
+Database version 2021c
+
+Generated on 2022-08-07
+
+https://github.com/evansiroky/timezone-boundary-builder/releases/tag/2021c
diff --git a/Sources/SwiftTimeZoneLookup/Resources/timezone16.bin b/Sources/SwiftTimeZoneLookup/Resources/timezone16.bin
new file mode 100644
index 0000000..7fca9b9
Binary files /dev/null and b/Sources/SwiftTimeZoneLookup/Resources/timezone16.bin differ
diff --git a/Sources/SwiftTimeZoneLookup/Resources/timezone21.bin b/Sources/SwiftTimeZoneLookup/Resources/timezone21.bin
new file mode 100644
index 0000000..ea31a61
Binary files /dev/null and b/Sources/SwiftTimeZoneLookup/Resources/timezone21.bin differ
diff --git a/Sources/SwiftTimeZoneLookup/SwiftTimeZoneLookup.swift b/Sources/SwiftTimeZoneLookup/SwiftTimeZoneLookup.swift
index e6433a0..c23669f 100644
--- a/Sources/SwiftTimeZoneLookup/SwiftTimeZoneLookup.swift
+++ b/Sources/SwiftTimeZoneLookup/SwiftTimeZoneLookup.swift
@@ -1,6 +1,40 @@
-public struct SwiftTimeZoneLookup {
-    public private(set) var text = "Hello, World!"
+@_implementationOnly import CZoneDetect
+import Foundation
 
-    public init() {
+public enum SwiftTimeZoneLookupError: Error {
+    case couldNotFindTimezone21bin
+    case couldNotOpenDatabase
+}
+
+public final class SwiftTimeZoneLookup {
+    private let database: OpaquePointer
+    
+    public init() throws {
+        guard let timezone21 = Bundle.module.url(forResource: "timezone21", withExtension: "bin") else {
+            throw SwiftTimeZoneLookupError.couldNotFindTimezone21bin
+        }
+        
+        guard let database = timezone21.withUnsafeFileSystemRepresentation({ timezone21 in
+            ZDOpenDatabase(timezone21)
+        }) else {
+            throw SwiftTimeZoneLookupError.couldNotOpenDatabase
+        }
+        self.database = database
+        
+        
+        print(timezone21)
+    }
+    
+    public func lookup(latitude: Float, longitude: Float) -> String {
+        guard let cTimezone = ZDHelperSimpleLookupString(database, latitude, longitude) else {
+            fatalError()
+        }
+        let timezone = String(cString: cTimezone)
+        ZDHelperSimpleLookupStringFree(cTimezone)
+        return timezone
+    }
+    
+    deinit {
+        ZDCloseDatabase(database)
     }
 }
diff --git a/Tests/SwiftTimeZoneLookupTests/SwiftTimeZoneLookupTests.swift b/Tests/SwiftTimeZoneLookupTests/SwiftTimeZoneLookupTests.swift
index a74b47d..3c4394a 100644
--- a/Tests/SwiftTimeZoneLookupTests/SwiftTimeZoneLookupTests.swift
+++ b/Tests/SwiftTimeZoneLookupTests/SwiftTimeZoneLookupTests.swift
@@ -2,10 +2,11 @@ import XCTest
 @testable import SwiftTimeZoneLookup
 
 final class SwiftTimeZoneLookupTests: XCTestCase {
-    func testExample() throws {
-        // This is an example of a functional test case.
-        // Use XCTAssert and related functions to verify your tests produce the correct
-        // results.
-        XCTAssertEqual(SwiftTimeZoneLookup().text, "Hello, World!")
+    func testLookup() throws {
+        let database = try SwiftTimeZoneLookup()
+        XCTAssertEqual(database.lookup(latitude: 47.5, longitude: 8.6), "Europe/Zurich")
+        XCTAssertEqual(database.lookup(latitude: 47.5, longitude: -2.6), "Europe/Paris")
+        XCTAssertEqual(database.lookup(latitude: 47.5, longitude: -8.6), "Etc/GMT+1")
+        XCTAssertEqual(database.lookup(latitude: 42.5, longitude: -8.6), "Europe/Madrid")
     }
 }