The Sierra Madre is the longest mountain range in the Philippines. Spanning for over 540 kilometers, it runs from the province of Cagayan down to the province of Quezon, forming a north–south direction on the eastern portion of Luzon.

Sigiriya is located in the Matale District in the Central Province of Sri Lanka. It is located within the cultural triangle formed by Anuradhapura, Polonnaruwa and Kandy which includes five of the eight world heritage sites in Sri Lanka.

Sigulda is a town in the Vidzeme Region of Latvia, 53 kilometres from the capital city Riga.

There are many islands off the Cambodian coast that have lots of coral and fish. All the dive boats in Cambodia leave from the Sihanoukville port area.

Silhouette Island lies 20 km northwest of Mahé in Seychelles. It is the third-largest granitic island in Seychelles.

Egypt’s Sinai Peninsula is a sparsely populated desert region between the Red Sea and the Mediterranean Sea. On its southern tip, Sharm el-Sheikh resort is a base for diving and snorkeling around the reefs of Ras Mohammed National Park.

Sinaia is a town in central Romania’s Bucegi Mountains, surrounded by ski trails. Its 17th-century Sinaia Monastery was once a royal family residence. German neo-Renaissance Peleș Castle, now a museum, has Klimt frescoes and stained-glass windows.

Sincholagua is an inactive volcano located in Ecuador 17 km (11 mi) northeast of Cotopaxi Volcano and 45 km (28 mi) southeast of Quito. ... Due to its close proximity to Cotopaxi, the second highest peak in Ecuador and the most popular volcano.

The Singalila Ridge is a north-south mountain ridge running from northwestern West Bengal through Sikkim in the Indian part of the Himalayas. The district of Ilam in Nepal falls on the western part of this ridge.

Singapore, officially the Republic of Singapore, is a sovereign island city-state in maritime Southeast Asia.