diff --git a/docs/Makefile b/docs/Makefile
index 7001b80..ab2ffdd 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -3,7 +3,7 @@ all: sphinx
 
 # No -W for doctests because that disallows tests with empty output.
 SPHINX_DOCTEST_OPTS=-n -d build/doctress .
-SPHINXOPTS=-n -W -d build/doctrees .
+SPHINXOPTS=-n -d build/doctrees .
 
 .PHONY: sphinx
 sphinx:
diff --git a/docs/conf.py b/docs/conf.py
index 368e4e8..85a276d 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -17,7 +17,6 @@ extensions = [
     "sphinx.ext.coverage",
     "sphinx.ext.doctest",
     "sphinx.ext.extlinks",
-    "sphinx.ext.intersphinx",
     "sphinx.ext.viewcode",
     ]
 
@@ -92,10 +91,6 @@
         'tornado-%s.tar.g' % version),
     }
 
-intersphinx_mapping = {
-    'python': ('https://docs.python.org/3.5/', None),
-    }
-
 on_rtd = os.environ.get('READTHEDOCS', None) == 'True'
 
 # On RTD we can't import sphinx_rtd_theme, but it will be applied by