diff --git a/crates/storage/src/collections.rs b/crates/storage/src/collections.rs
index 952b20ae5..1686eaf26 100644
--- a/crates/storage/src/collections.rs
+++ b/crates/storage/src/collections.rs
@@ -20,15 +20,12 @@ pub mod error;
 pub use error::StoreError;
 
 // fixme! macro expects `calimero_storage` to be in deps
-use crate as calimero_storage;
 use crate::address::{Id, Path};
 use crate::entities::{Data, Element};
 use crate::interface::{Interface, StorageError};
-use crate::{AtomicUnit, Collection};
+use crate::{self as calimero_storage, AtomicUnit, Collection};
 
 #[derive(AtomicUnit, BorshSerialize, BorshDeserialize, Clone, Debug)]
-#[type_id(255)]
-#[root]
 struct Collection<T> {
     /// The entries in the collection.
     #[collection]
@@ -82,7 +79,6 @@ struct Entries<T> {
 
 /// An entry in a map.
 #[derive(AtomicUnit, BorshSerialize, BorshDeserialize, Clone, Debug)]
-#[type_id(254)]
 struct Entry<T> {
     /// The item in the entry.
     item: T,
@@ -107,14 +103,24 @@ type StoreResult<T> = std::result::Result<T, StoreError>;
 
 impl<T: BorshSerialize + BorshDeserialize> Collection<T> {
     /// Creates a new collection.
-    fn new() -> Self {
+    fn new(id: Option<Id>) -> Self {
+        let id = id.unwrap_or_else(|| Id::random());
+
         let mut this = Self {
             entries: Entries::default(),
             children_ids: RefCell::new(None),
-            storage: Element::new(&Path::new("::unused").expect("valid path"), None),
+            storage: Element::new(&Path::new("::unused").expect("valid path"), Some(id)),
         };
 
-        let _ = Interface::save(&mut this).expect("save collection");
+        if id.is_root() {
+            let _ignored = Interface::save(&mut this).expect("save");
+        } else {
+            let root = root::ROOT
+                .with(|root| root.borrow().clone())
+                .expect("no root??");
+
+            let _ = Interface::add_child_to(root.id, &root, &mut this).expect("add child");
+        }
 
         this
     }
diff --git a/crates/storage/src/collections/root.rs b/crates/storage/src/collections/root.rs
index 5a2280e61..2d5d8823c 100644
--- a/crates/storage/src/collections/root.rs
+++ b/crates/storage/src/collections/root.rs
@@ -1,13 +1,45 @@
 //! A root collection that stores a single value.
 
 use std::cell::RefCell;
+use std::marker::PhantomData;
 use std::ptr;
 
 use borsh::{BorshDeserialize, BorshSerialize};
-use calimero_sdk::env;
 
-use super::Collection;
+use super::{Collection, Entry};
 use crate::address::Id;
+use crate::entities::Data;
+use crate::env;
+
+/// Thing.
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub struct RootHandle<T> {
+    /// The ID of the root collection.
+    pub id: Id,
+    _priv: PhantomData<T>,
+}
+
+impl<T: Data> RootHandle<T> {
+    fn new(id: Id) -> Self {
+        Self {
+            id,
+            _priv: PhantomData,
+        }
+    }
+}
+
+impl<T: Data> crate::entities::Collection for RootHandle<T> {
+    type Child = T;
+
+    fn name(&self) -> &str {
+        "RootHandle"
+    }
+}
+
+thread_local! {
+    /// The root collection handle.
+    pub static ROOT: RefCell<Option<RootHandle<Entry<()>>>> = RefCell::new(None);
+}
 
 /// A set collection that stores unqiue values once.
 #[derive(Clone, Debug, BorshSerialize, BorshDeserialize)]
@@ -25,7 +57,13 @@ where
     pub fn new(value: T) -> Self {
         let id = Id::new(env::context_id());
 
-        let mut inner = Collection::new();
+        let old = ROOT.with(|root| root.borrow_mut().replace(RootHandle::new(id)));
+
+        if old.is_some() {
+            panic!("root collection already defined");
+        }
+
+        let mut inner = Collection::new(Some(id));
 
         let value = inner.insert(Some(id), value).unwrap();
 
diff --git a/crates/storage/src/collections/unordered_map.rs b/crates/storage/src/collections/unordered_map.rs
index 017261514..d122baf3c 100644
--- a/crates/storage/src/collections/unordered_map.rs
+++ b/crates/storage/src/collections/unordered_map.rs
@@ -26,7 +26,7 @@ where
     ///
     pub fn new() -> Self {
         Self {
-            inner: Collection::new(),
+            inner: Collection::new(None),
         }
     }
 
@@ -198,9 +198,12 @@ where
 #[cfg(test)]
 mod tests {
     use crate::collections::unordered_map::UnorderedMap;
+    use crate::collections::Root;
 
     #[test]
     fn test_unordered_map_basic_operations() {
+        let _root = Root::new(());
+
         let mut map = UnorderedMap::<String, String>::new();
 
         assert!(map
@@ -250,6 +253,8 @@ mod tests {
 
     #[test]
     fn test_unordered_map_insert_and_get() {
+        let _root = Root::new(());
+
         let mut map = UnorderedMap::<String, String>::new();
 
         assert!(map
@@ -273,6 +278,8 @@ mod tests {
 
     #[test]
     fn test_unordered_map_update_value() {
+        let _root = Root::new(());
+
         let mut map = UnorderedMap::<String, String>::new();
 
         assert!(map
@@ -292,6 +299,8 @@ mod tests {
 
     #[test]
     fn test_remove() {
+        let _root = Root::new(());
+
         let mut map = UnorderedMap::<String, String>::new();
 
         assert!(map
@@ -308,6 +317,8 @@ mod tests {
 
     #[test]
     fn test_clear() {
+        let _root = Root::new(());
+
         let mut map = UnorderedMap::<String, String>::new();
 
         assert!(map
@@ -327,6 +338,8 @@ mod tests {
 
     #[test]
     fn test_unordered_map_len() {
+        let _root = Root::new(());
+
         let mut map = UnorderedMap::<String, String>::new();
 
         assert_eq!(map.len().expect("len failed"), 0);
@@ -356,6 +369,8 @@ mod tests {
 
     #[test]
     fn test_unordered_map_contains() {
+        let _root = Root::new(());
+
         let mut map = UnorderedMap::<String, String>::new();
 
         assert!(map
@@ -369,6 +384,8 @@ mod tests {
 
     #[test]
     fn test_unordered_map_entries() {
+        let _root = Root::new(());
+
         let mut map = UnorderedMap::<String, String>::new();
 
         assert!(map
diff --git a/crates/storage/src/collections/unordered_set.rs b/crates/storage/src/collections/unordered_set.rs
index 4781ba5f0..cb36a2599 100644
--- a/crates/storage/src/collections/unordered_set.rs
+++ b/crates/storage/src/collections/unordered_set.rs
@@ -24,7 +24,7 @@ where
     ///
     pub fn new() -> Self {
         Self {
-            inner: Collection::new(),
+            inner: Collection::new(None),
         }
     }
 
@@ -171,10 +171,12 @@ where
 
 #[cfg(test)]
 mod tests {
-    use crate::collections::UnorderedSet;
+    use crate::collections::{Root, UnorderedSet};
 
     #[test]
     fn test_unordered_set_operations() {
+        let _root = Root::new(());
+
         let mut set = UnorderedSet::<String>::new();
 
         assert!(set.insert("value1".to_string()).expect("insert failed"));
@@ -203,6 +205,8 @@ mod tests {
 
     #[test]
     fn test_unordered_set_len() {
+        let _root = Root::new(());
+
         let mut set = UnorderedSet::<String>::new();
 
         assert!(set.insert("value1".to_string()).expect("insert failed"));
@@ -218,6 +222,8 @@ mod tests {
 
     #[test]
     fn test_unordered_set_clear() {
+        let _root = Root::new(());
+
         let mut set = UnorderedSet::<String>::new();
 
         assert!(set.insert("value1".to_string()).expect("insert failed"));
@@ -234,6 +240,8 @@ mod tests {
 
     #[test]
     fn test_unordered_set_entries() {
+        let _root = Root::new(());
+
         let mut set = UnorderedSet::<String>::new();
 
         assert!(set.insert("value1".to_string()).expect("insert failed"));
diff --git a/crates/storage/src/collections/vector.rs b/crates/storage/src/collections/vector.rs
index b797e69fd..c3310e095 100644
--- a/crates/storage/src/collections/vector.rs
+++ b/crates/storage/src/collections/vector.rs
@@ -22,7 +22,7 @@ where
     ///
     pub fn new() -> Self {
         Self {
-            inner: Collection::new(),
+            inner: Collection::new(None),
         }
     }
 
@@ -159,9 +159,12 @@ where
 #[cfg(test)]
 mod tests {
     use crate::collections::vector::Vector;
+    use crate::collections::Root;
 
     #[test]
     fn test_vector_push() {
+        let _root = Root::new(());
+
         let mut vector: Vector<String> = Vector::new();
         let value = "test_data".to_string();
         let result = vector.push(value.clone());
@@ -171,6 +174,8 @@ mod tests {
 
     #[test]
     fn test_vector_get() {
+        let _root = Root::new(());
+
         let mut vector: Vector<String> = Vector::new();
         let value = "test_data".to_string();
         let _ = vector.push(value.clone()).unwrap();
@@ -180,6 +185,8 @@ mod tests {
 
     #[test]
     fn test_vector_update() {
+        let _root = Root::new(());
+
         let mut vector: Vector<String> = Vector::new();
         let value1 = "test_data1".to_string();
         let value2 = "test_data2".to_string();
@@ -192,6 +199,8 @@ mod tests {
 
     #[test]
     fn test_vector_get_non_existent() {
+        let _root = Root::new(());
+
         let vector: Vector<String> = Vector::new();
         match vector.get(0) {
             Ok(retrieved_value) => assert_eq!(retrieved_value, None),
@@ -201,6 +210,8 @@ mod tests {
 
     #[test]
     fn test_vector_pop() {
+        let _root = Root::new(());
+
         let mut vector: Vector<String> = Vector::new();
         let value = "test_data".to_string();
         let _ = vector.push(value.clone()).unwrap();
@@ -211,6 +222,8 @@ mod tests {
 
     #[test]
     fn test_vector_entries() {
+        let _root = Root::new(());
+
         let mut vector: Vector<String> = Vector::new();
         let value1 = "test_data1".to_string();
         let value2 = "test_data2".to_string();
@@ -222,6 +235,8 @@ mod tests {
 
     #[test]
     fn test_vector_contains() {
+        let _root = Root::new(());
+
         let mut vector: Vector<String> = Vector::new();
         let value = "test_data".to_string();
         let _ = vector.push(value.clone()).unwrap();
@@ -232,6 +247,8 @@ mod tests {
 
     #[test]
     fn test_vector_clear() {
+        let _root = Root::new(());
+
         let mut vector: Vector<String> = Vector::new();
         let value = "test_data".to_string();
         let _ = vector.push(value.clone()).unwrap();
diff --git a/crates/storage/src/entities.rs b/crates/storage/src/entities.rs
index 01f5b3af5..211ba676e 100644
--- a/crates/storage/src/entities.rs
+++ b/crates/storage/src/entities.rs
@@ -788,6 +788,7 @@ pub struct Metadata {
     pub(crate) updated_at: UpdatedAt,
 }
 
+/// The timestamp when the [`Element`] was last updated.
 #[derive(
     BorshDeserialize, BorshSerialize, Copy, Clone, Debug, Default, Eq, Hash, Ord, PartialOrd,
 )]