diff --git a/srtm4/download.py b/srtm4/download.py
index ffdb9cb..1a8dcb6 100644
--- a/srtm4/download.py
+++ b/srtm4/download.py
@@ -14,10 +14,11 @@
 import os
 
 import requests
+from requests.auth import HTTPBasicAuth
 from requests.adapters import HTTPAdapter, Retry, RetryError
 import filelock
 
-SRTM_URL = 'https://srtm.csi.cgiar.org/wp-content/uploads/files/srtm_5x5/TIFF'
+SRTM_URL = 'https://e4ftl01.cr.usgs.gov//DP133/SRTM/SRTMGL1.003/2000.02.11'
 
 
 def _requests_retry_session(
@@ -59,6 +60,7 @@ def download(to_file, from_url):
     # Use a requests session with retry logic because the server at
     # SRTM_URL sometimes returns 503 responses when overloaded
     session = _requests_retry_session()
+    
     r = session.get(from_url, stream=True, verify=False)
     if not r.ok:
         raise ConnectionError(
@@ -102,8 +104,9 @@ def get_srtm_tile(srtm_tile, out_dir):
         return
 
     # download the zip file
-    srtm_tile_url = '{}/{}.zip'.format(SRTM_URL, srtm_tile)
-    zip_path = os.path.join(output_dir, '{}.zip'.format(srtm_tile))
+    x, y = srtm_tile
+    srtm_tile_url = f'{SRTM_URL}/{y}{x}.SRTMGL1.hgt.zip'
+    zip_path = os.path.join(output_dir, f'{y}_{x}.zip')
 
     lock_zip = filelock.FileLock(srtm_zip_download_lock)
     lock_zip.acquire()
diff --git a/srtm4/point.py b/srtm4/point.py
index 1fbfd3d..66c4086 100644
--- a/srtm4/point.py
+++ b/srtm4/point.py
@@ -33,6 +33,21 @@ def lon_lats_str(lon, lat):
     return lon_lats
 
 
+def tile_from_lon_lat(lon, lat):
+    if lon < 0:
+        lon_direction = "W"
+    else:
+        lon_direction = "E"
+    if lat < 0:
+        lat_direction = "S"
+    else:
+        lat_direction = "N"
+        
+    lon = int(lon)
+    lat = int(lat)
+    
+    return f"{lon_direction}{str(lon).zfill(3)}", f"{lat_direction}{str(lat).zfill(2)}"
+        
 def srtm4_which_tile(lon, lat):
     """
     Determine the srtm tiles needed to cover the (list of) point(s)
@@ -70,10 +85,10 @@ def srtm4(lon, lat):
     """
     # get the names of srtm_tiles needed
     srtm_tiles = srtm4_which_tile(lon, lat)
-
+    srtm_tile_lon, srtm_tile_lat = tile_from_lon_lat(lon, lat)
     # download the tiles if not already there
     for srtm_tile in set(srtm_tiles):
-        download.get_srtm_tile(srtm_tile, SRTM_DIR)
+        download.get_srtm_tile((srtm_tile_lon, srtm_tile_lat), SRTM_DIR)
 
     # run the srtm4 binary and feed it from stdin
     lon_lats = lon_lats_str(lon, lat)