diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3910a28..c2d269c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -61,3 +61,4 @@ foreach(FILE ${ALL_FILES})
 endforeach()
 
 set_property(TEST three_regions.vpy PROPERTY WILL_FAIL true)
+set_property(TEST leak_with_global.vpy PROPERTY WILL_FAIL true)
diff --git a/src/lang/interpreter.cc b/src/lang/interpreter.cc
index 631f3c7..894cbd4 100644
--- a/src/lang/interpreter.cc
+++ b/src/lang/interpreter.cc
@@ -125,8 +125,8 @@ namespace verona::interpreter
         std::cout << node->location().view() << std::endl << std::endl;
 
         // Mermaid output
-        std::vector<rt::objects::Edge> edges{{nullptr, "?", frame()}};
-        ui->output(edges, std::string(node->location().view()));
+        std::vector<rt::objects::DynObject*> roots{frame()};
+        ui->output(roots, std::string(node->location().view()));
 
         // Continue
         return ExecNext{};
@@ -464,12 +464,13 @@ namespace verona::interpreter
       out.open(path);
     }
 
-    void output(std::vector<rt::objects::Edge>& edges, std::string message)
+    void
+    output(std::vector<rt::objects::DynObject*>& roots, std::string message)
     {
       out << "```" << std::endl;
       out << message << std::endl;
       out << "```" << std::endl;
-      rt::ui::mermaid(edges, out);
+      rt::ui::mermaid(roots, out);
       if (interactive)
       {
         out.close();
diff --git a/src/rt/core.h b/src/rt/core.h
index d3c86e5..e4acfc0 100644
--- a/src/rt/core.h
+++ b/src/rt/core.h
@@ -3,14 +3,13 @@
 
 namespace rt::core
 {
-
   class PrototypeObject : public objects::DynObject
   {
     std::string name;
 
   public:
     PrototypeObject(std::string name_, objects::DynObject* prototype = nullptr)
-    : objects::DynObject(prototype, true), name(name_)
+    : objects::DynObject(prototype), name(name_)
     {}
 
     std::string get_name()
@@ -21,15 +20,19 @@ namespace rt::core
     }
   };
 
-  PrototypeObject framePrototypeObject{"Frame"};
+  inline PrototypeObject* framePrototypeObject()
+  {
+    static PrototypeObject* proto = new PrototypeObject("Frame");
+    return proto;
+  }
 
   class FrameObject : public objects::DynObject
   {
-    FrameObject() : objects::DynObject(&framePrototypeObject, true) {}
+    FrameObject() : objects::DynObject(framePrototypeObject(), true) {}
 
   public:
     FrameObject(objects::DynObject* parent_frame)
-    : objects::DynObject(&framePrototypeObject)
+    : objects::DynObject(framePrototypeObject())
     {
       if (parent_frame)
       {
@@ -45,9 +48,17 @@ namespace rt::core
     }
   };
 
-  PrototypeObject funcPrototypeObject{"Function"};
-  PrototypeObject bytecodeFuncPrototypeObject{
-    "BytecodeFunction", &funcPrototypeObject};
+  inline PrototypeObject* funcPrototypeObject()
+  {
+    static PrototypeObject* proto = new PrototypeObject("Function");
+    return proto;
+  }
+  inline PrototypeObject* bytecodeFuncPrototypeObject()
+  {
+    static PrototypeObject* proto =
+      new PrototypeObject("BytecodeFunction", funcPrototypeObject());
+    return proto;
+  }
 
   class FuncObject : public objects::DynObject
   {
@@ -63,7 +74,7 @@ namespace rt::core
 
   public:
     BytecodeFuncObject(verona::interpreter::Bytecode* body_)
-    : FuncObject(&bytecodeFuncPrototypeObject), body(body_)
+    : FuncObject(bytecodeFuncPrototypeObject()), body(body_)
     {}
     ~BytecodeFuncObject()
     {
@@ -77,15 +88,19 @@ namespace rt::core
     }
   };
 
-  PrototypeObject stringPrototypeObject{"String"};
+  inline PrototypeObject* stringPrototypeObject()
+  {
+    static PrototypeObject* proto = new PrototypeObject("String");
+    return proto;
+  }
 
   class StringObject : public objects::DynObject
   {
     std::string value;
 
   public:
-    StringObject(std::string value_, bool global = false)
-    : objects::DynObject(&stringPrototypeObject, global), value(value_)
+    StringObject(std::string value_)
+    : objects::DynObject(stringPrototypeObject()), value(value_)
     {}
 
     std::string get_name()
@@ -106,12 +121,23 @@ namespace rt::core
     }
   };
 
-  StringObject TrueObject{"True", true};
-  StringObject FalseObject{"False", true};
+  inline StringObject* trueObject()
+  {
+    static StringObject* val = new StringObject("True");
+    return val;
+  }
+  inline StringObject* falseObject()
+  {
+    static StringObject* val = new StringObject("False");
+    return val;
+  }
 
   // The prototype object for iterators
-  // TODO put some stuff in here?
-  PrototypeObject keyIterPrototypeObject{"KeyIterator"};
+  inline PrototypeObject* keyIterPrototypeObject()
+  {
+    static PrototypeObject* proto = new PrototypeObject("KeyIterator");
+    return proto;
+  }
 
   class KeyIterObject : public objects::DynObject
   {
@@ -120,7 +146,7 @@ namespace rt::core
 
   public:
     KeyIterObject(std::map<std::string, objects::DynObject*>& fields)
-    : objects::DynObject(&keyIterPrototypeObject),
+    : objects::DynObject(keyIterPrototypeObject()),
       iter(fields.begin()),
       iter_end(fields.end())
     {}
@@ -147,4 +173,19 @@ namespace rt::core
       return this;
     }
   };
+
+  inline std::set<objects::DynObject*>* globals()
+  {
+    static std::set<objects::DynObject*>* globals =
+      new std::set<objects::DynObject*>{
+        framePrototypeObject(),
+        funcPrototypeObject(),
+        bytecodeFuncPrototypeObject(),
+        stringPrototypeObject(),
+        keyIterPrototypeObject(),
+        trueObject(),
+        falseObject(),
+      };
+    return globals;
+  }
 } // namespace rt::core
diff --git a/src/rt/objects/dyn_object.h b/src/rt/objects/dyn_object.h
index 5306e53..ac6e2b5 100644
--- a/src/rt/objects/dyn_object.h
+++ b/src/rt/objects/dyn_object.h
@@ -28,7 +28,7 @@ namespace rt::objects
     friend class Reference;
     friend objects::DynObject* rt::make_iter(objects::DynObject* obj);
     friend void
-    rt::ui::mermaid(std::vector<objects::Edge>& roots, std::ostream& out);
+    rt::ui::mermaid(std::vector<objects::DynObject*>& roots, std::ostream& out);
     friend void destruct(DynObject* obj);
     friend void dealloc(DynObject* obj);
     template<typename Pre, typename Post>
@@ -170,10 +170,10 @@ namespace rt::objects
 
   public:
     // prototype is borrowed, the caller does not need to provide an RC.
-    DynObject(DynObject* prototype_ = nullptr, bool global = false)
+    DynObject(DynObject* prototype_ = nullptr, bool first_frame = false)
     : prototype(prototype_)
     {
-      if (!global)
+      if (!first_frame)
       {
         count++;
         all_objects.insert(this);
@@ -181,9 +181,10 @@ namespace rt::objects
         region = local_region;
         local_region->objects.insert(this);
       }
+
       if (prototype != nullptr)
         prototype->change_rc(1);
-      std::cout << "Allocate: " << get_name() << std::endl;
+      std::cout << "Allocate: " << this << std::endl;
     }
 
     // TODO This should use prototype lookup for the destructor.
@@ -198,7 +199,10 @@ namespace rt::objects
       // RC is zero.
       if (change_rc(0) != 0 && matched != 0)
       {
-        ui::error("Object still has references");
+        std::stringstream stream;
+        stream << this;
+        stream << "  still has references";
+        ui::error(stream.str());
       }
 
       auto r = get_region(this);
diff --git a/src/rt/rt.cc b/src/rt/rt.cc
index 439e87a..6c46386 100644
--- a/src/rt/rt.cc
+++ b/src/rt/rt.cc
@@ -3,7 +3,9 @@
 #include "core.h"
 #include "objects/dyn_object.h"
 
+#include <algorithm>
 #include <iostream>
+#include <set>
 #include <string>
 #include <vector>
 
@@ -54,7 +56,7 @@ namespace rt
   {
     // TODO Add some checking.  This is need to lookup the correct function in
     // the prototype chain.
-    if (key->get_prototype() != &core::stringPrototypeObject)
+    if (key->get_prototype() != core::stringPrototypeObject())
     {
       ui::error("Key must be a string.");
     }
@@ -96,11 +98,11 @@ namespace rt
 
   objects::DynObject* get_true()
   {
-    return &core::TrueObject;
+    return core::trueObject();
   }
   objects::DynObject* get_false()
   {
-    return &core::FalseObject;
+    return core::falseObject();
   }
 
   void add_reference(objects::DynObject* src, objects::DynObject* target)
@@ -123,6 +125,9 @@ namespace rt
 
   size_t pre_run()
   {
+    std::cout << "Initilizing global objects" << std::endl;
+    core::globals();
+
     std::cout << "Running test..." << std::endl;
     return objects::DynObject::get_count();
   }
@@ -131,17 +136,27 @@ namespace rt
   {
     std::cout << "Test complete - checking for cycles in local region..."
               << std::endl;
+    auto globals = core::globals();
     if (objects::DynObject::get_count() != initial_count)
     {
       std::cout << "Cycles detected in local region." << std::endl;
-      auto objs = objects::DynObject::get_local_region()->get_objects();
-      std::vector<objects::Edge> edges;
-      for (auto obj : objs)
-      {
-        edges.push_back({nullptr, "?", obj});
-      }
-      ui.output(edges, "Cycles detected in local region.");
+      auto roots = objects::DynObject::get_local_region()->get_objects();
+      roots.erase(
+        std::remove_if(
+          roots.begin(),
+          roots.end(),
+          [&globals](auto x) { return globals->contains(x); }),
+        roots.end());
+      ui.output(roots, "Cycles detected in local region.");
     }
+
+    // Freeze global objects, to low the termination of the local region
+    std::cout << "Freezing global objects" << std::endl;
+    for (auto obj : *globals)
+    {
+      obj->freeze();
+    }
+
     objects::DynObject::get_local_region()->terminate_region();
     if (objects::DynObject::get_count() != initial_count)
     {
@@ -150,12 +165,12 @@ namespace rt
       std::cout << "Final count: " << objects::DynObject::get_count()
                 << std::endl;
 
-      std::vector<objects::Edge> edges;
+      std::vector<objects::DynObject*> roots;
       for (auto obj : objects::DynObject::get_objects())
       {
-        edges.push_back({nullptr, "?", obj});
+        roots.push_back(obj);
       }
-      ui.output(edges, "Memory leak detected!");
+      ui.output(roots, "Memory leak detected!");
 
       std::exit(1);
     }
@@ -168,7 +183,7 @@ namespace rt
   objects::DynObject* iter_next(objects::DynObject* iter)
   {
     assert(!iter->is_immutable());
-    if (iter->get_prototype() != &core::keyIterPrototypeObject)
+    if (iter->get_prototype() != core::keyIterPrototypeObject())
     {
       ui::error("Object is not an iterator.");
     }
@@ -178,7 +193,7 @@ namespace rt
 
   verona::interpreter::Bytecode* get_bytecode(objects::DynObject* func)
   {
-    if (func->get_prototype() == &core::bytecodeFuncPrototypeObject)
+    if (func->get_prototype() == core::bytecodeFuncPrototypeObject())
     {
       return reinterpret_cast<core::BytecodeFuncObject*>(func)->get_bytecode();
     }
diff --git a/src/rt/ui.h b/src/rt/ui.h
index cb81967..18a824e 100644
--- a/src/rt/ui.h
+++ b/src/rt/ui.h
@@ -12,10 +12,10 @@ namespace rt::ui
   class UI
   {
   public:
-    virtual void output(std::vector<objects::Edge>&, std::string) {}
+    virtual void output(std::vector<objects::DynObject*>&, std::string) {}
   };
 
-  void mermaid(std::vector<objects::Edge>& roots, std::ostream& out);
+  void mermaid(std::vector<objects::DynObject*>& roots, std::ostream& out);
 
   [[noreturn]] inline void error(const std::string& msg)
   {
diff --git a/src/rt/ui/mermaid.cc b/src/rt/ui/mermaid.cc
index 809b20c..29a432b 100644
--- a/src/rt/ui/mermaid.cc
+++ b/src/rt/ui/mermaid.cc
@@ -1,3 +1,4 @@
+#include "../core.h"
 #include "../objects/dyn_object.h"
 #include "../ui.h"
 
@@ -30,7 +31,7 @@ namespace rt::ui
     return text;
   }
 
-  void mermaid(std::vector<objects::Edge>& roots, std::ostream& out)
+  void mermaid(std::vector<objects::DynObject*>& roots, std::ostream& out)
   {
     // Give a nice id to each object.
     std::map<objects::DynObject*, std::size_t> visited;
@@ -56,6 +57,10 @@ namespace rt::ui
       objects::DynObject* dst = e.target;
       std::string key = e.key;
       objects::DynObject* src = e.src;
+      if (unreachable && core::globals()->contains(dst))
+      {
+        return false;
+      }
       if (src != nullptr)
       {
         out << "  id" << visited[src] << " -->|" << escape(key) << "| ";
@@ -85,10 +90,10 @@ namespace rt::ui
       }
       return true;
     };
-    // Output all reachable edges
+    // Output all reachable nodes
     for (auto& root : roots)
     {
-      objects::visit({root.src, root.key, root.target}, explore);
+      objects::visit(root, explore);
     }
 
     // Output the unreachable parts of the graph
diff --git a/tests/leak_with_global.vpy b/tests/leak_with_global.vpy
new file mode 100644
index 0000000..74d6d14
--- /dev/null
+++ b/tests/leak_with_global.vpy
@@ -0,0 +1,3 @@
+str = "example"
+
+str["__proto__"].dummy = {}