request fails on wikipedia (https) - certificate verify failed (_ssl.c:748)

[F Massion]

Hi,

I would like to get information from Wikipedia articles and I am testing the connection to Wikipedia. 

I am running Python 3.6.2 on Windows 10.

I get certificate errors for all pages with https. 
Any suggestions are welcome!

Here my code:

import requests, bs4
from bs4 import BeautifulSoup
res = requests.get('https://en.wikipedia.org/wiki/Stethoscope')
type(res)
res.status_code == requests.codes.ok
wiki = bs4.BeautifulSoup(res.text)
type(wiki)
len(res.text)
print(res.text[:250])

Here the error message:

Traceback (most recent call last):
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\urllib3\connectionpool.py", line 601, in urlopen
    chunked=chunked)
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\urllib3\connectionpool.py", line 346, in _make_request
    self._validate_conn(conn)
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\urllib3\connectionpool.py", line 850, in _validate_conn
    conn.connect()
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\urllib3\connection.py", line 326, in connect
    ssl_context=context)
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\urllib3\util\ssl_.py", line 329, in ssl_wrap_socket
    return context.wrap_socket(sock, server_hostname=server_hostname)
  File "c:\Program Files (x86)\Python36-32\lib\ssl.py", line 401, in wrap_socket
    _context=self, _session=session)
  File "c:\Program Files (x86)\Python36-32\lib\ssl.py", line 808, in __init__
    self.do_handshake()
  File "c:\Program Files (x86)\Python36-32\lib\ssl.py", line 1061, in do_handshake
    self._sslobj.do_handshake()
  File "c:\Program Files (x86)\Python36-32\lib\ssl.py", line 683, in do_handshake
    self._sslobj.do_handshake()
ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:748)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\requests\adapters.py", line 440, in send
    timeout=timeout
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\urllib3\connectionpool.py", line 639, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\urllib3\util\retry.py", line 388, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))
urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='en.wikipedia.org', port=443): Max retries exceeded with url: /wiki/Stethoscope (Caused by SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:748)'),))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "web_1.py", line 3, in <module>
    res = requests.get('https://en.wikipedia.org/wiki/Stethoscope')
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\requests\api.py", line 72, in get
    return request('get', url, params=params, **kwargs)
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\requests\api.py", line 58, in request
    return session.request(method=method, url=url, **kwargs)
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\requests\sessions.py", line 508, in request
    resp = self.send(prep, **send_kwargs)
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\requests\sessions.py", line 618, in send
    r = adapter.send(request, **kwargs)
  File "c:\Program Files (x86)\Python36-32\lib\site-packages\requests\adapters.py", line 506, in send
    raise SSLError(e, request=request)
requests.exceptions.SSLError: HTTPSConnectionPool(host='en.wikipedia.org', port=443): Max retries exceeded with url: /wiki/Stethoscope (Caused by SSLError(SSLError(1, '[SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:748)'),))