diff --git a/babel/dates.py b/babel/dates.py
index 7b626aa11..b2244466c 100644
--- a/babel/dates.py
+++ b/babel/dates.py
@@ -528,10 +528,10 @@ def get_timezone_location(
     territory = get_global('zone_territories').get(zone)
     if territory not in locale.territories:
         territory = 'ZZ'  # invalid/unknown
-    territory_name = locale.territories[territory]
+    territory_name = locale.territories.get(territory)
     if (
         not return_city
-        and territory
+        and territory_name
         and len(get_global('territory_zones').get(territory, [])) == 1
     ):
         return region_format % territory_name
@@ -552,6 +552,10 @@ def get_timezone_location(
 
     if return_city:
         return city_name
+    if territory_name is None:
+        # The locale has no name for the zone's region, not even for the
+        # "unknown region" fallback, so the region is left out.
+        return region_format % city_name
     return region_format % (
         fallback_format
         % {
@@ -1480,7 +1484,7 @@ def __getitem__(self, name: str) -> str:
         else:
             raise KeyError(f"Unsupported date/time field {char!r}")
 
-    def extract(self, char: str) -> int:
+    def extract(self, char: str) -> int | str:
         char = str(char)[0]
         if char == 'y':
             return self.value.year
@@ -1496,6 +1500,12 @@ def extract(self, char: str) -> int:
             return self.value.minute
         elif char == 'a':
             return int(self.value.hour >= 12)  # 0 for am, 1 for pm
+        elif char == 'G':
+            return int(self.value.year >= 0)  # 0 for BCE, 1 for CE
+        elif char == 'B':
+            # The day period is rendered from the same identifier,
+            # so the extracted value matches what `format_period` renders.
+            return get_period_id(self.value, locale=self.locale)
         else:
             raise NotImplementedError(
                 f"Not implemented: extracting {char!r} from {self.value!r}",
diff --git a/tests/test_date_intervals.py b/tests/test_date_intervals.py
index 33a85d38a..ee52b75c1 100644
--- a/tests/test_date_intervals.py
+++ b/tests/test_date_intervals.py
@@ -61,3 +61,32 @@ def test_issue_825():
         locale='pt',
     )
     assert formatted == '1 h'
+
+
+@pytest.mark.parametrize(
+    ("start", "end", "skeleton", "expected"),
+    [
+        # Era ('G') interval formats used to raise NotImplementedError when
+        # computing the greatest difference between the two instants.
+        # A year difference must select the 'y' pattern of the "Gy" interval format.
+        (TEST_DT, TEST_DT.replace(year=2017), "Gy", "2016\u2009\u2013\u20092017 AD"),
+        (
+            TEST_DT,
+            TEST_DT.replace(year=2017, month=3),
+            "GyM",
+            "1/2016\u2009\u2013\u20093/2017 AD",
+        ),
+        # Day period ('B') interval formats used to raise NotImplementedError, too.
+        # Differing day periods must select the 'B' pattern of the "Bh" interval format.
+        (
+            TEST_DT,
+            TEST_DT.replace(hour=16),
+            "Bh",
+            "11 in the morning\u2009\u2013\u20094 in the afternoon",
+        ),
+        # ... and a shared day period must fall through to the 'h' pattern.
+        (TEST_DT, TEST_DT.replace(hour=10), "Bh", "11\u2009\u2013\u200910 in the morning"),
+    ],
+)
+def test_format_interval_era_and_day_period(start, end, skeleton, expected):
+    assert dates.format_interval(start, end, skeleton, locale="en") == expected
diff --git a/tests/test_dates.py b/tests/test_dates.py
index 4f8c73907..2297db18c 100644
--- a/tests/test_dates.py
+++ b/tests/test_dates.py
@@ -284,6 +284,17 @@ def test_get_timezone_location(timezone_getter):
             'Deutschland (Berlin) (Ortszeit)')
 
 
+def test_get_timezone_location_without_a_region_name(timezone_getter):
+    # Locales without a name for the "unknown region" (CLDR "ZZ") used to
+    # raise a KeyError instead of falling back to the location without region.
+    tz = timezone_getter('America/St_Johns')
+    assert dates.get_timezone_location(tz, locale='aa') == 'St. John’s'
+    assert dates.get_timezone_location(tz, locale='aa', return_city=True) == 'St. John’s'
+    assert dates.get_timezone_name(tz, locale='aa') == 'St. John’s'
+    # Locales that do have a name for it are unchanged.
+    assert dates.get_timezone_location(tz, locale='en') == 'Canada (St. John’s) Time'
+
+
 @pytest.mark.parametrize(
     ('tzname', 'params', 'expected'),
     [