diff --git a/2023/day5/.gitignore b/2023/day5/.gitignore
new file mode 100644
index 0000000..b83d222
--- /dev/null
+++ b/2023/day5/.gitignore
@@ -0,0 +1 @@
+/target/
diff --git a/2023/day5/Cargo.lock b/2023/day5/Cargo.lock
new file mode 100644
index 0000000..73006f1
--- /dev/null
+++ b/2023/day5/Cargo.lock
@@ -0,0 +1,126 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "autocfg"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d468802bab17cbc0cc575e9b053f41e72aa36bfa6b7f55e3529ffa43161b97fa"
+
+[[package]]
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+
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+dependencies = [
+ "cfg-if",
+ "crossbeam-epoch",
+ "crossbeam-utils",
+]
+
+[[package]]
+name = "crossbeam-epoch"
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+dependencies = [
+ "autocfg",
+ "cfg-if",
+ "crossbeam-utils",
+ "memoffset",
+ "scopeguard",
+]
+
+[[package]]
+name = "crossbeam-utils"
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+dependencies = [
+ "cfg-if",
+]
+
+[[package]]
+name = "day5"
+version = "0.1.0"
+dependencies = [
+ "indoc",
+ "nom",
+ "rayon",
+]
+
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+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
+name = "memchr"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
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+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a634b1c61a95585bd15607c6ab0c4e5b226e695ff2800ba0cdccddf208c406c"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "minimal-lexical"
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+source = "registry+https://github.com/rust-lang/crates.io-index"
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+
+[[package]]
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+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
+[[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 = "scopeguard"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
diff --git a/2023/day5/Cargo.toml b/2023/day5/Cargo.toml
new file mode 100644
index 0000000..ae6f898
--- /dev/null
+++ b/2023/day5/Cargo.toml
@@ -0,0 +1,11 @@
+[package]
+name = "day5"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+indoc = "2.0.4"
+nom = "7.1.3"
+rayon = "1.8.0"
diff --git a/2023/day5/src/main.rs b/2023/day5/src/main.rs
new file mode 100644
index 0000000..7ff0440
--- /dev/null
+++ b/2023/day5/src/main.rs
@@ -0,0 +1,322 @@
+use std::ops::Range;
+
+use nom::{
+    bytes::complete::{tag, take_until},
+    character::complete::{char, digit1, multispace0, multispace1},
+    combinator::map,
+    multi::{many1, separated_list1},
+    sequence::{preceded, separated_pair, terminated, tuple},
+    IResult,
+};
+use rayon::prelude::*;
+
+fn number(i: &str) -> IResult<&str, usize> {
+    map(digit1, |f: &str| f.parse::<usize>().unwrap())(i)
+}
+
+fn spaces(i: &str) -> IResult<&str, Vec<char>> {
+    many1(char(' '))(i)
+}
+
+fn ident(i: &str) -> IResult<&str, &str> {
+    take_until(" ")(i)
+}
+
+#[derive(Debug)]
+struct Almanac<S: Seeds> {
+    seeds: Box<S>,
+    map_lists: Vec<MapList>,
+}
+
+impl<S: Seeds<Out = S>> Almanac<S> {
+    fn parse(s: &str) -> IResult<&str, Self> {
+        let map_lists = separated_list1(multispace1, MapList::parse);
+        let (rest, (seeds, map_lists)) = terminated(
+            separated_pair(<S as Seeds>::parse, multispace1, map_lists),
+            multispace0,
+        )(s)?;
+        Ok((rest, Self { seeds, map_lists }))
+    }
+}
+
+#[derive(Debug)]
+struct SeedList(Vec<usize>);
+
+#[derive(Debug)]
+struct SeedRanges(Vec<Range<usize>>);
+
+trait Seeds {
+    type Out: Seeds;
+    fn parse(s: &str) -> IResult<&str, Box<Self::Out>>;
+}
+
+impl Seeds for SeedList {
+    type Out = Self;
+    fn parse(s: &str) -> IResult<&str, Box<Self::Out>> {
+        let (rest, ids) = preceded(tag("seeds: "), separated_list1(char(' '), number))(s)?;
+        Ok((rest, Box::new(Self(ids))))
+    }
+}
+
+impl Seeds for SeedRanges {
+    type Out = Self;
+    fn parse(s: &str) -> IResult<&str, Box<Self::Out>> {
+        let (rest, range) = preceded(
+            tag("seeds: "),
+            separated_list1(char(' '), separated_pair(number, spaces, number)),
+        )(s)?;
+        Ok((
+            rest,
+            Box::new(Self(
+                range
+                    .into_iter()
+                    .map(|(start, length)| start..start + length)
+                    .collect(),
+            )),
+        ))
+    }
+}
+
+#[derive(Debug)]
+struct Map {
+    source_range: Range<usize>,
+    destination_range: Range<usize>,
+}
+
+impl Map {
+    fn parse(s: &str) -> IResult<&str, Self> {
+        let (rest, (destination_start, source_start, length)) = tuple((
+            terminated(number, spaces),
+            terminated(number, spaces),
+            number,
+        ))(s)?;
+        Ok((
+            rest,
+            Self {
+                source_range: source_start..(source_start + length),
+                destination_range: destination_start..(destination_start + length),
+            },
+        ))
+    }
+
+    fn map(&self, value: usize) -> Option<usize> {
+        if self.source_range.contains(&value) {
+            let index = value - self.source_range.start;
+            // `nth()` is implemented via a simple addition, there is no actual calling
+            // of `next()`
+            Some(self.destination_range.clone().nth(index).unwrap())
+        } else {
+            None
+        }
+    }
+}
+
+#[derive(Debug)]
+struct MapList {
+    #[allow(dead_code)]
+    header: String,
+    maps: Vec<Map>,
+}
+
+impl MapList {
+    fn parse(s: &str) -> IResult<&str, Self> {
+        let maps = separated_list1(multispace1, Map::parse);
+        let header = terminated(ident, tag(" map:"));
+
+        let (rest, (header, maps)) = separated_pair(header, multispace1, maps)(s)?;
+
+        Ok((
+            rest,
+            Self {
+                header: header.to_owned(),
+                maps,
+            },
+        ))
+    }
+
+    fn map(&self, value: usize) -> usize {
+        for map in &self.maps {
+            if let Some(mapped_value) = map.map(value) {
+                return mapped_value;
+            }
+        }
+        value
+    }
+}
+
+fn part1(input: &str) -> Result<usize, String> {
+    let (rest, almanac) = Almanac::<SeedList>::parse(input).map_err(|e| e.to_string())?;
+    if !rest.is_empty() {
+        println!("parsing rest found: {rest}");
+        panic!();
+    }
+    let mut lowest_location = usize::MAX;
+    for seed in &almanac.seeds.0 {
+        let mut mapped_value = *seed;
+        for map_list in &almanac.map_lists {
+            mapped_value = map_list.map(mapped_value);
+        }
+        if mapped_value < lowest_location {
+            lowest_location = mapped_value;
+        }
+    }
+    Ok(lowest_location)
+}
+
+fn part2(input: &str) -> Result<usize, String> {
+    let (rest, almanac) = Almanac::<SeedRanges>::parse(input).map_err(|e| e.to_string())?;
+    if !rest.is_empty() {
+        println!("parsing rest found: {rest}");
+        panic!();
+    }
+    let lowest_location = almanac
+        .seeds
+        .0
+        .into_par_iter()
+        .map(|seed_range| {
+            println!("{seed_range:?}");
+            // let seeds = seed_range.collect::<Vec<usize>>();
+            let result = seed_range
+                .clone()
+                .map(|seed| {
+                    let mut mapped_value = seed;
+                    for map_list in &almanac.map_lists {
+                        mapped_value = map_list.map(mapped_value);
+                    }
+                    mapped_value
+                })
+                .min()
+                .unwrap();
+            println!("{seed_range:?} => {result}");
+            result
+        })
+        .min()
+        .unwrap();
+    Ok(lowest_location)
+}
+
+fn main() -> Result<(), String> {
+    let input = include_str!("../input");
+
+    println!("Part 1 : {}", part1(input)?);
+    println!("Part 2 : {}", part2(input)?);
+
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use indoc::indoc;
+
+    #[test]
+    fn example_01() {
+        let input = indoc! {"
+            seeds: 79 14 55 13
+
+            seed-to-soil map:
+            50 98 2
+            52 50 48
+
+            soil-to-fertilizer map:
+            0 15 37
+            37 52 2
+            39 0 15
+
+            fertilizer-to-water map:
+            49 53 8
+            0 11 42
+            42 0 7
+            57 7 4
+
+            water-to-light map:
+            88 18 7
+            18 25 70
+
+            light-to-temperature map:
+            45 77 23
+            81 45 19
+            68 64 13
+
+            temperature-to-humidity map:
+            0 69 1
+            1 0 69
+
+            humidity-to-location map:
+            60 56 37
+            56 93 4
+        "};
+
+        assert_eq!(part1(&input).unwrap(), 35);
+    }
+
+    #[test]
+    fn test_map() {
+        let input = indoc! {"
+            50 98 2
+        "};
+
+        let (_rest, map) = Map::parse(input).unwrap();
+        assert_eq!(map.map(97), None);
+        assert_eq!(map.map(98), Some(50));
+        assert_eq!(map.map(99), Some(51));
+        assert_eq!(map.map(100), None);
+        assert_eq!(map.map(101), None);
+    }
+
+    #[test]
+    fn test_map_list() {
+        let input = indoc! {"
+            seed-to-soil map:
+            50 98 2
+            52 50 48
+        "};
+
+        let (_rest, maplist) = MapList::parse(input).unwrap();
+        assert_eq!(maplist.map(79), 81);
+        assert_eq!(maplist.map(14), 14);
+        assert_eq!(maplist.map(55), 57);
+        assert_eq!(maplist.map(13), 13);
+    }
+
+    #[test]
+    fn example_02() {
+        let input = indoc! {"
+            seeds: 79 14 55 13
+
+            seed-to-soil map:
+            50 98 2
+            52 50 48
+
+            soil-to-fertilizer map:
+            0 15 37
+            37 52 2
+            39 0 15
+
+            fertilizer-to-water map:
+            49 53 8
+            0 11 42
+            42 0 7
+            57 7 4
+
+            water-to-light map:
+            88 18 7
+            18 25 70
+
+            light-to-temperature map:
+            45 77 23
+            81 45 19
+            68 64 13
+
+            temperature-to-humidity map:
+            0 69 1
+            1 0 69
+
+            humidity-to-location map:
+            60 56 37
+            56 93 4
+        "};
+
+        assert_eq!(part2(&input).unwrap(), 46);
+    }
+}