diff --git a/django_netjsongraph/api/generics.py b/django_netjsongraph/api/generics.py
index 31a33a0..7fae835 100644
--- a/django_netjsongraph/api/generics.py
+++ b/django_netjsongraph/api/generics.py
@@ -37,7 +37,10 @@ class BaseNetworkGraphHistoryView(APIView):
     def get(self, request, pk, format=None):
         topology = get_object_or_404(self.topology_model, pk)
         date = request.query_params.get('date')
-        options = dict(topology=topology, date=date)
+        kind = request.query_params.get('kind')
+        if not kind:
+            kind = "normal"
+        options = dict(topology=topology, date=date, kind=kind)
         # missing date: 400
         if not date:
             return Response({'detail': _('missing required "date" parameter')},
diff --git a/django_netjsongraph/base/snapshot.py b/django_netjsongraph/base/snapshot.py
index 2792ed0..aca79fc 100644
--- a/django_netjsongraph/base/snapshot.py
+++ b/django_netjsongraph/base/snapshot.py
@@ -2,6 +2,7 @@
 from django.utils.translation import ugettext_lazy as _
 
 from .base import TimeStampedEditableModel
+from .topology import SNAPSHOT_KINDS
 
 
 class AbstractSnapshot(TimeStampedEditableModel):
@@ -11,6 +12,11 @@ class AbstractSnapshot(TimeStampedEditableModel):
     topology = models.ForeignKey('django_netjsongraph.topology')
     data = models.TextField(blank=False)
     date = models.DateField(auto_now=True)
+    kind = models.CharField(_('kind'),
+                            max_length=16,
+                            choices=SNAPSHOT_KINDS,
+                            default=SNAPSHOT_KINDS[0],
+                            db_index=True)
 
     class Meta:
         verbose_name_plural = _('snapshots')
diff --git a/django_netjsongraph/base/topology.py b/django_netjsongraph/base/topology.py
index 802e2e5..e07649c 100644
--- a/django_netjsongraph/base/topology.py
+++ b/django_netjsongraph/base/topology.py
@@ -12,6 +12,9 @@
 from django.utils.translation import ugettext_lazy as _
 from netdiff import NetJsonParser, diff
 from rest_framework.utils.encoders import JSONEncoder
+from netdiff.utils import _netjson_networkgraph as to_netjson
+from netjson_robustness.analyser import ParsedGraph
+
 
 from ..contextmanagers import log_failure
 from ..settings import PARSERS, TIMEOUT
@@ -23,6 +26,13 @@
     ('receive', _('RECEIVE'))
 )
 
+# TODO export these in the configuration
+# First element is default
+SNAPSHOT_KINDS = (
+    ('normal', _('NORMAL')),
+    ('block_cut_tree', _('BLOCK_CUT_TREE'))
+)
+
 
 @python_2_unicode_compatible
 class AbstractTopology(TimeStampedEditableModel):
@@ -254,16 +264,34 @@ def save_snapshot(self, **kwargs):
         """
         Saves the snapshot of topology
         """
-        Snapshot = self.snapshot_model
-        date = datetime.now().date()
-        options = dict(topology=self, date=date)
-        options.update(kwargs)
-        try:
-            s = Snapshot.objects.get(**options)
-        except:
-            s = Snapshot(**options)
-        s.data = self.json()
-        s.save()
+        for kind in SNAPSHOT_KINDS:
+            Snapshot = self.snapshot_model
+            date = datetime.now().date()
+            options = dict(topology=self, date=date, kind=kind[0])
+            options.update(kwargs)
+            try:
+                s = Snapshot.objects.get(**options)
+            except:
+                s = Snapshot(**options)
+
+            if kind[0] == "block_cut_tree":
+                s.data = self.compute_cut_block_tree()
+            elif kind[0] == "normal":
+                s.data = self.json()
+            s.save()
+
+    def compute_cut_block_tree(self):
+        """
+        transform a given topology in a cut-block tree for better
+        visualization of the critical nodes
+        """
+        netjson = NetJsonParser(self.json(dict=True, omit_down=True))
+        p = ParsedGraph(netjson)
+        p.condensate_graph()
+        return json.dumps(to_netjson(p.netJSON.protocol, p.netJSON.version,
+                          p.netJSON.revision, p.netJSON.metric,
+                          p.condensed_graph.nodes(data=True),
+                          p.condensed_graph.edges(data=True), dict=True))
 
     def link_status_changed(self, link, status):
         """
diff --git a/django_netjsongraph/static/netjsongraph/js/topology-history.js b/django_netjsongraph/static/netjsongraph/js/topology-history.js
index 2dcf2d9..a30539b 100644
--- a/django_netjsongraph/static/netjsongraph/js/topology-history.js
+++ b/django_netjsongraph/static/netjsongraph/js/topology-history.js
@@ -2,16 +2,22 @@ window.initTopologyHistory = function($){
     var datepicker = $('#njg-datepicker'),
         today = new Date(),
         apiUrl = datepicker.attr('data-history-api');
+    var kindpicker=$("input[name='visualization_kind']");
+    var kind = 'normal';
+    kindpicker.change(function() {;
+        kind = this.value
+    });
     today.setHours(0, 0, 0, 0);
     datepicker.datepicker({dateFormat: 'dd/mm/yy'});
     datepicker.datepicker('setDate', today);
     datepicker.change(function() {;
         var date = datepicker.val().split('/').reverse().join('-'),
-            url = apiUrl + '?date=' + date;
+            url = apiUrl + '?kind=' + kind + '&date=' + date;
         // load latest data when looking currentDate
         if(datepicker.datepicker('getDate').getTime() == today.getTime()){
             url = window.__njg_default_url__;
         }
+        // load latest data when looking currentDate
         $.getJSON(url).done(function(data){
             window.graph = window.loadNetJsonGraph(data);
         }).error(function(xhr){
diff --git a/django_netjsongraph/templates/netjsongraph/netjsongraph-content.html b/django_netjsongraph/templates/netjsongraph/netjsongraph-content.html
index d94cd52..cfe4855 100644
--- a/django_netjsongraph/templates/netjsongraph/netjsongraph-content.html
+++ b/django_netjsongraph/templates/netjsongraph/netjsongraph-content.html
@@ -4,7 +4,13 @@
     <p><span class="link down">&nbsp;</span> {% trans 'link down' %}</p>
 </div>
 <div class="njg-switcher">
+    <form id="v_kind">
+    <legend>Choose Visualization</legend>
     <label for="njg-datepicker">{% trans 'date' %}:</label>
     <input type="text" id="njg-datepicker"
-           data-history-api="{{ history_url }}">
+                       data-history-api="{{ history_url }}"><br/>
+    <input type="radio" name="visualization_kind" id="normal" value="normal"><label for="normal">{% trans 'normal' %}</label><br/>
+    <input type="radio" name="visualization_kind" id="block_cut_tree" value="block_cut_tree"><label for="block_cut_tree">{% trans 'block-cut-tree' %}</label><br/>
+    </form>
+
 </div>