diff --git a/Cargo.lock b/Cargo.lock
index 5cd08e4..7ed9a3d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -7,6 +7,7 @@ name = "advent-of-code-2023"
 version = "0.1.0"
 dependencies = [
  "automod",
+ "rayon",
  "regex",
  "scan_fmt",
  "serde_json",
@@ -21,6 +22,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "autocfg"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
+
 [[package]]
 name = "automod"
 version = "1.0.13"
@@ -32,6 +39,51 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
+[[package]]
+name = "crossbeam-deque"
+version = "0.8.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ce6fd6f855243022dcecf8702fef0c297d4338e226845fe067f6341ad9fa0cef"
+dependencies = [
+ "cfg-if",
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
+version = "0.9.15"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae211234986c545741a7dc064309f67ee1e5ad243d0e48335adc0484d960bcc7"
+dependencies = [
+ "autocfg",
+ "cfg-if",
+ "crossbeam-utils",
+ "memoffset",
+ "scopeguard",
+]
+
+[[package]]
+name = "crossbeam-utils"
+version = "0.8.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a22b2d63d4d1dc0b7f1b6b2747dd0088008a9be28b6ddf0b1e7d335e3037294"
+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "either"
+version = "1.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a26ae43d7bcc3b814de94796a5e736d4029efb0ee900c12e2d54c993ad1a1e07"
+
 [[package]]
 name = "itoa"
 version = "1.0.9"
@@ -44,6 +96,15 @@ version = "2.6.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f665ee40bc4a3c5590afb1e9677db74a508659dfd71e126420da8274909a0167"
 
+[[package]]
+name = "memoffset"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a634b1c61a95585bd15607c6ab0c4e5b226e695ff2800ba0cdccddf208c406c"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.70"
@@ -62,6 +123,26 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "rayon"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c27db03db7734835b3f53954b534c91069375ce6ccaa2e065441e07d9b6cdb1"
+dependencies = [
+ "either",
+ "rayon-core",
+]
+
+[[package]]
+name = "rayon-core"
+version = "1.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5ce3fb6ad83f861aac485e76e1985cd109d9a3713802152be56c3b1f0e0658ed"
+dependencies = [
+ "crossbeam-deque",
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "regex"
 version = "1.10.2"
@@ -106,6 +187,12 @@ dependencies = [
  "regex",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
+
 [[package]]
 name = "serde"
 version = "1.0.193"
diff --git a/Cargo.toml b/Cargo.toml
index 42b4e05..cc4b2b6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,6 +7,7 @@ edition = "2021"
 
 [dependencies]
 automod = "1.0.13"
+rayon = "1.8.0"
 regex = "1.10.2"
 scan_fmt = "0.2.6"
 serde_json = "1.0.108"
diff --git a/src/days/d03.rs b/src/days/d03.rs
index 1e6fa64..5a8da65 100644
--- a/src/days/d03.rs
+++ b/src/days/d03.rs
@@ -1,6 +1,8 @@
+use rayon::prelude::*;
 use regex::Regex;
 use std::collections::HashMap;
 use std::fs;
+use std::sync::{Arc, Mutex};
 
 pub fn solve() {
     let path = "res/03/input";
@@ -13,11 +15,13 @@ pub fn solve() {
         .map(|l| l.chars().collect::<Vec<char>>())
         .collect();
 
-    let mut possible_gears = HashMap::<(usize, usize), Vec<usize>>::new();
+    let possible_gears: Arc<Mutex<HashMap<(usize, usize), Vec<usize>>>> =
+        Arc::new(Mutex::new(HashMap::new()));
 
     let result: usize = contents
         .lines()
         .enumerate()
+        .par_bridge()
         .map(|(yusize, line)| {
             let re = Regex::new(r"(\d+)").unwrap();
             let y = yusize as i32;
@@ -48,7 +52,8 @@ pub fn solve() {
                         })
                         .map(|(x, y)| {
                             if grid[*y as usize][*x as usize] == '*' {
-                                possible_gears
+                                let mut possible_gears_mut = possible_gears.lock().unwrap();
+                                possible_gears_mut
                                     .entry((*x as usize, *y as usize))
                                     .or_insert(vec![])
                                     .push(number);
@@ -70,7 +75,8 @@ pub fn solve() {
 
     println!("Result 1: {}", result);
 
-    let result: usize = possible_gears
+    let possible_gears_mut = possible_gears.lock().unwrap();
+    let result: usize = possible_gears_mut
         .iter()
         .filter(|(_, vec)| vec.len() == 2)
         .map(|(_, vec)| vec.iter().product::<usize>())