At one time, around one third of the land mass of the Earth was under British Control. All of the following were under the control of the British on or around the start of the 20th century:
Australia
New Zealand
South Africa
Canada
Sudan (Now two separate countries)
Egypt
India (Now three separate countries)
Burma (Now Myanmar)
Malaya (Now part of Malaysia)
Nigeria
Kenya
Tanganyika (Now Tanzania)
Uganda
Rhodesia (Now Zimbabwe)
Singapore
Palestine (Now Israel and Jordan (mainly))
Ghana
Sierra Leone
Iraq
British Honduras (Now Belize)
Somaliland
Bechuanaland (Now part of South Africa)
Afghanistan
Ireland
Java
The Gulf States
Bermuda
The Falkland Islands
Cyprus
Malta
Nyasaland (now Malawi)
Swaziland
Zanzibar
Anguila
Antigua
Barbados
Grenada
Jamaica
Ceylon (now Sri Lanka)
Hong Kong
Sarawak (Now part of Malaysia)
Gibraltar
The Seychelles
New Guinea
Fiji
The Gambia
There were loads of small Island nations too. And what a mess (mainly) we left them all in (especially Palestine).