import re


def extract_timestamp(caption, pattern=r'(\d{4}(:|/)\d{2}(:|/)\d{2})', split=True):
    """
    Return a string with date and time extracted from the given string
    """
    match = re.split(pattern, caption)
    try:
        date = match[1]
        time = match[-1].split()[0]
    except IndexError:
        raise ValueError('Problem extracting timestamp from caption', caption)
    return ' '.join([date, time])